Possible Relief for Several A500 ICS Related Symptoms/ProblemsTips

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  1. Mrhelper

    Mrhelper Well-Known Member

    5-15-2012: Further down in this post are workarounds for an a500 ICS screen auto rotate problem.
    The primary symptom is a g-sensor/accelerometer hang which prevents automatic screen rotation/orientation. This is accompanied by MLUpdateData error (code 26) messages in logs. If you are here for that, scroll down to the section titled: "MOTION SENSOR INITIALIZATION PROBLEM." If not, the following section may help you resolve a number of app issues affecting ICS.

    You may have arrived here with other problems (because of the somewhat ambiguous title), and may not have observed the auto rotate problem. There may be something here for you also, and I've moved that to the top of this post, so please read on. The sensor problem and associated tips are still in the lower portion of this post.

    What follows are more general tips to help alleviate numerous problems that people are seeing.

    There have been numerous complaints relative to ICS on that a500 on various forums about problematic system behavior -- app crashes, wifi problems, display flashes, slow response, and general instability. After using ICS on the a500 for over two weeks now, seeing solutions to numerous problems posted, and based on considerable testing I've done, I'm convinced that most problems seen with ICS are caused by apps that are not entirely compatible with ICS on the a500. I've also noticed that app fixes for ICS are still coming in, and that many similar issues have occurred with other devices upon migration to ICS. This is to be expected considering that there are thousands of apps available, and these are written by thousands of developers. The following tips may be useful in helping you solve your particular problems. If your problem is not caused by some app that you have installed, you are likely in a very small minority of users.

    Many users are having success in working around various problems by simply removing unused apps. I've noticed that many are accomplishing this by using the factory data reset option, which clears out all apps. They then merely reload fewer apps, and reduce the risk of running problematic ones. Fewer apps installed appears to correlate with higher stability.

    Use of this tip may significantly reduce the number of problems people are encountering with their A500, A200, and possibly A100 tablets.

    To avoid sending your tablet into Acer for a factory data reset (something you can do at home anyway), try the following:
    * remove any apps that are force closing or otherwise crashing
    * remove apps that you don't use. Having fewer apps installed reduces the risk of having problems.
    * avoid parking Dolphin or the stock browser in the background with open tabs. Close tabs and exit the browser when you are done. If you often "temporarily" park your browsers in the background as I do, and this seems like a very typical/normal user behavior, consider installing Watchdog to see when browsers start to consume significant CPU resource in the background. If you monitor for this, you can deal with it. If you ignore it, you may not understand what is happening when other symptoms occur -- and several that I have seen have been severe.
    * don't kill apps
    * remove app managers, task killers, performance improver apps, anything that kills apps (if you still want to watch your system resources, use OS Monitor or Watchdog, but don't use the app/process kill functions, use the reset button if something is hung).
    * use the hardware reset button (or at least lock screen rotation via the switch) if your system slows, wifi stops working well, screen rotation hangs, etc.

    If the solutions noted above don't work, your best bet is a controlled factory data reset. This appears to have helped many after the ICS update, myself included. By "controlled," I mean you should follow the instructions below to methodically determine which apps have been causing problems on the system.

    If you have backed up your important data, then there is nothing to lose by doing the factory data reset. If you have not backed up important data, it is very likely that you are going to lose those anyway, and when you least expect it, or when you can least tolerate it ...so simply plug in a USB flash stick, and copy your valuable data from the internal "sdcard" to the stick. Use ES File Manager or a similarly reliable app. You can alternately/also backup easily to a PC using the mini USB adapter cable that came with your tablet (you may have to install the a500 USB driver from the Acer site). With ES File Manager, you can even back up most of your installed app APK files for future reference or use, in which case, you can put those on your backup also.

    If you already have good backups of your important data, then it takes less time to do the factory reset than to ask or even think about it. It will: remove everything from the built-in "sdcard" flash memory, remove every app, configure all settings to defaults, etc. It restores your device to the system that Acer apparently used to test the ICS release. It will not restore to an older version of Android than you are currently running, so if you are running ICS, you get a fresh factory image of ICS. It's like getting a brand new tablet.

    Here's how you do the factory data reset (after you have backed up your data on your PC or an other form of external storage):

    1.) Go to Settings->Backup & Reset->Factory Data Reset. Follow the prompts to accept the reset.

    2.) When the factory data reset completes in a few seconds, and the system boots up, set up your wifi

    3.) When you are prompted to login to your google account, do not turn on the Google automatic app/data restore feature. Decline that option when asked. That setting is used to restore apps automatically and if left on, may restore the problem(s) you were having. If you miss the prompt, immediately go into settings/backups & reset and uncheck Automatic Restore. You must do this before starting Google Plat, and before Google Play starts to restore apps and app data, so it does not simply reinstall the problem(s) you were having. (If you miss this step, start over and repeat the factory data reset.)

    4.) After the tablet setup is complete, use Google Play to update the built in apps only. Do not install any apps until you have tested your tablet with the built-in browser, email, etc.

    5.) For at least 24 hours, test with only the built in apps, or if you feel things are going very well, and are willing to tolerate more risk (of having to start over) proceed slowly with adding apps.

    6.) If you determine that the tablet works OK now without all of your other apps installed, then you need to methodically eliminate the bad app or apps that were causing problems.

    If you do the factory reset, and then just reload all of the same apps again, then you can expect the problems to return. That is likely why some report that the factory data reset does not work for them -- i.e., because they just reloaded all of the same apps which caused the same problems.

    After factory data reset:
    * Be very selective in choosing apps to install, especially while testing ICS with your tablet.
    * Screen apps by reading app reviews for your tablet (in GooglePlay reviews, select newest instead of most helpful, also select for this tablet only)
    * Install apps slowly and methodically, at a rate of no more than 1-2 per day if possible. Keep track of the order in which you install apps.
    * Test each app carefully. When you install a new app, verify that other problems are not starting to occur. When problems do occur start removing apps in the opposite order in which you loaded them, to isolate bad apps. Keeping track of the order of installation facilitates this process.


    The MPU initialization does fail as a result of a race condition as I suspected, but the race was not nearly as close as I thought.

    I have been able to reproduce the InvenSense MPU-3050 initialization failure at will, and can also _prevent_ it now over 95% of the time. The problem appears to be the result of the MPU-3050 not shutting down entirely until a significant period of time has passed after an a500 power down. This effect can often be seen by powering down the tablet, and then immediately powering it back up, where all MPU-3050 sensors are then unavailable, and associated features like automatic screen rotation do not function. The condition persists until manually cleared by the user as described below.

    I've observed that there are two ways to clear the MPU initialization failure condition, and one way that usually prevents it, but as I write in a followup post is not quite 100% effective:

    ** To clear the condition in less than 30 seconds, just press the hardware reset button (pinhole). The hardware reset appears to shorten the associated MPU-3050 shutdown period, possibly by shorting down residual voltage that may be delaying restart. It's hard to determine the precise cause without having more detailed specs on a500 internals, but this seems to be a reasonable theory.

    ** An alternate way to clear the condition is to power off the a500, and wait at least 5 minutes before powering back up. This may allow residual voltage on the MPU to drain prior to restart, and thus permit normal initialization of sensors at power up. Again, a theory, but a reasonable one based on past experience with other systems.

    ** To reduce the chances of encountering the problem, do not power the a500 back on until at least 5 minutes after power down. I would not be surprised to learn that some a500s take less time, and others take more. It appears that many a500s may rarely if ever exhibit the problem. I actually saw some good restarts at power cycle intervals closer to 1 minute. I just got to a point where I thought I was splitting hairs, became bored with the repeated testing, and settled on 5 minutes.

    The method I suggest for prevention -- i.e., not using short power up/down cycles -- is probably the natural behavior for most users, and one reason why many report never seeing the problem. I can't rule out that there may be subtle differences in hardware between a500 owners either, because I've only tested this so far on my own tablet, so some users may not be able to reproduce the problem at all.

    Apparently then, a500 owners like me who have been seeing this problem more regularly, have possibly been testing for this or other problems, and actually increasing the frequency by performing that specific test -- i.e., the short power up/down cycle. I first saw this sensor problem while repeatedly powering up/down to diagnose problems that I was seeing with certain apps after the ICS update. Others who have detected this problem are possibly behaving similarly while working on other tasks where they perform short power down/up cycles.

    It seems possible that the root XDA build that cryptonym tried merely had some other problem with MPU initialization, and that the cause for his error code 26 issue with that ROM installed may have a different origin. Maybe, maybe not. It could be that it is the same problem, and the boot is just that much faster regardless of whether the reset or power button is used.

    Android ICS did come with some code changes relative to the MPU though -- specifically in the use of the gyro to reduce latency and smooth output for the gravity sensor, the linear acceleration sensor, and the rotation vector sensor. This may or may not have anything to do with the problem, but seems worth mentioning.

    I can now prevent the problem more effectively, but it is clearly a bug in the a500 OS, and one that appears to have been delivered with ICS.

    Below is a continuation of the original post on the motion sensor (MPU) error:
    (I am a little concerned about not separating this entire post into two posts, because this talks about two issues -- i.e., more general app management practices, and this specific sensor error condition. I'm leaving it as one though because I see it is being referenced more lately, and readers may be expecting to see one or both issues under the current title.)

    An obvious early symptom is the loss of automatic screen orientation (auto rotate). Power off/on will not always clear this. Locking the screen orientation by sliding the lock switch to the right will pause the errors.

    What happens: Power up boots of the a500 in this version of ICS intermittently fail to initialize the MPU 3050 sensor device, and the log then shows a constant stream of MLUpdateData error (code 26) messages. The "aLogcat" app from the Market is handy for seeing errors like this. There may be an impact to system resources while the errors are occurring, but I have not determined how significant the direct impact is. The associated sensor errors are posted to the log every 50ms... that's 20 times each second. Again, sliding the auto rotate switch to the locked position apparently suspends the sensor error condition, and reduces some symptoms as long as the switch stays locked. Unlocking causes the rapidly repeating MLUpdateData errors to immediately resume.

    If I never power the unit off after a hardware reset (pressing the pinhole button, not the "factory data reset"), I never see the problem occur. One workaround then is to avoid powering the unit down, and then when you occasionally do, use the reset button after power up if symptoms appear.

    The condition only starts immediately after a power off /on cycle. I observed that with a clean factory data restore, and no other apps installed, I could reproduce the problem more often by powering down immediately within 2-3 seconds after powering up, proving that this can be triggered without installing any applications beyond those provided in the OS package by Acer.

    Beyond the loss of automatic screen rotation, symptoms of the g-sensor error problem can be relatively mild, and at times, unnoticeable. I suspect that many users are generally satisfied with the performance of their tablet with this error occurring because they may not notice it.


    Below is an example of the MPU sensor error problem from logs on my a500. I've included part of the boot log output from a failed MPU init sequence, followed by log entries showing the E/Sensor MLUpdateData errors, and then finally a clean boot after a hardware reset with no MPU sensor errors.

    At power up, this problem always shows up in the system log with this error: E/Sensors ( 141): could not open the mpu irq device node

    The kernel log shows the actual start of the problem, where the mpu3050 does not respond to the probe.

    The MPU fails to initialize. This only appears to happen at power up, and not a during a hardware reset as otherwise initiated by the pinhole button.

    You can then see the MLUpdateData errors repeating every 50ms (20 times a second).

    When I flip the screen rotation lock switch to locked, another error is printed for MPL-mlstates.

    Flipping the switch to locked also "pauses" the errors, so this may be a handy temporary remedy if you are not ready to reset the device. Flipping it back to unlock allows the errors to continue, and the symptoms return.

    This appears then to be a problem with code using the InvenSense MPL (Motion Processing Library) driver/software in this version of ICS for the A500. It may be a timing problem, or some other problem with the initialization methods used in the code. Power off/on does not typically clear this, and as I have now concluded after more exhaustive testing, appears to be the final trigger for the problem.

    You can typically clear this condition temporarily after it has been triggered by pressing the hardware reset button (pinhole, lower right below the USB port). You can pause the errors and the associated performance impacts by setting the screen orientation lock switch to locked position. After a hardware reset, the condition then stays clear until the device is powered down and then back up.

    There may be some intermediate stimulus involving timing of actions by the user, because the device occasionally powers up without causing the problem. What I have found though is that after apps have been installed, the power off/on action tends to cause the problem about 50% of the time.


    In the kernel log excerpt below, look at time 2.609914. The i2c_readl() call by i2c-tegra.c|tegra_i2c_isr() returns 0x8 (I2C_INT_NO_ACK) while attempting to read status from the mpu3050, and so mpu3050_probe fails because the mpu3050 is apparently just not ready to respond when this happens.

    <6>[ 2.608737] compass sensor is AKM8975 0x48
    <6>[ 2.608899] i2c i2c-0: mpu3050: +kxtf9
    <6>[ 2.608989] i2c i2c-0: Installing Accel irq using 343
    <6>[ 2.609272] i2c i2c-0: mpu3050: +ak8975
    <6>[ 2.609434] i2c i2c-0: Installing Compass irq using 301
    <4>[ 2.609706] i2c i2c-0: mpu3050: No Pressure Present
    <4>[ 2.609914] tegra-i2c tegra-i2c.0: I2c error status 0x00000008
    <4>[ 2.610004] tegra-i2c tegra-i2c.0: no acknowledge from address 0x68
    <4>[ 2.610163] tegra-i2c tegra-i2c.0: Packet status 0x00010009
    <3>[ 2.611283] mldl_cfg:/home/pandora/pandora_build_root/main_rom/android/PicassoV041_A500_mdrr/kernel/drivers/misc/mpu3050/inv_330/mldl_cfg.c|MLDLPowerMgmtMPU|579 returning 135
    <3>[ 2.611520] mldl_cfg:/home/pandora/pandora_build_root/main_rom/android/PicassoV041_A500_mdrr/kernel/drivers/misc/mpu3050/inv_330/mldl_cfg.c|mpu3050_open|1225 returning 135
    <3>[ 2.611684] i2c i2c-0: Unable to open mpu3050 135
    <6>[ 2.611770] misc compassirq: Unregistering compassirq
    <6>[ 2.612052] misc accelirq: Unregistering accelirq
    <3>[ 2.612250] i2c i2c-0: mpu3050_probe failed -19
    <4>[ 2.612489] i2c-core: driver [mpu3050] using legacy suspend method
    <4>[ 2.612577] i2c-core: driver [mpu3050] using legacy resume method
    <7>[ 2.612741] mpu_init

    05-04 12:03:49.330 82 82 I dalvikvm: System server process 145 has been created
    05-04 12:03:49.330 82 82 I Zygote : Accepting command socket connections
    05-04 12:03:49.490 145 145 E BatteryService: usbOnlinePath not found
    05-04 12:03:49.510 145 145 I sysproc : Entered system_init()
    05-04 12:03:49.510 145 145 I sysproc : ServiceManager: 0x12f4788
    05-04 12:03:49.510 145 145 D SensorService: nuSensorService starting...
    05-04 12:03:49.590 145 145 V Sensors : sysapi object at 0x5afd6a1c
    05-04 12:03:49.590 145 145 V Sensors : sysapi getBiases func at 0x5afd176d
    05-04 12:03:49.590 145 145 E Sensors : could not open the mpu irq device node
    05-04 12:03:49.590 145 145 E Sensors : could not open the accel irq device node
    05-04 12:03:49.590 145 145 I MPL-mlsl: MLSLSerialOpen: /dev/mpu
    05-04 12:03:49.590 145 145 I MPL-mlsl: I2C Error: could not bind address 68: -1
    05-04 12:03:49.590 145 145 E Sensors : Fatal Error : could not open MPL serial interface
    05-04 12:03:49.590 145 145 E MPL-mlstates: Error : illegal state transition from ML_STATE_SERIAL_CLOSED to ML_STATE_DMP_OPENED
    05-04 12:03:49.590 145 145 E MPL-dmp : vendor/invensense/Invensense330/libsensors/mlsdk/mllite/mldmp.c|MLDmpOpen|82 returning 25
    05-04 12:03:49.590 145 145 E Sensors : Fatal Error : could not open DMP correctly.
    05-04 12:03:49.590 145 145 E Sensors : could not open MPL calibration file
    05-04 12:03:49.600 145 145 E MPL-mldl: DmpFeatureSupported : sGetAddress is NULL
    05-04 12:03:49.610 145 145 W MPL-9_sup: 9 axis sensor fusion not available - No compass detected.
    05-04 12:03:49.610 145 145 E Sensors : Error : Bias update function could not be set.
    05-04 12:03:49.610 145 145 E Sensors : Error : could not set motion interrupt
    05-04 12:03:49.610 145 145 E Sensors : Error : could not set fifo interrupt
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: MLSetFIFORate returned 26
    05-04 12:03:49.610 145 145 E Sensors : Error : Motion callback could not be set.
    05-04 12:03:49.610 145 145 E Sensors : Error : Processed data callback could not be set.
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: FIFOSendAccel returned 26
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: FIFOSendQuaternion returned 26
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: FIFOSendLinearAccel returned 26
    05-04 12:03:49.610 145 145 E MPL-fifo: vendor/invensense/Invensense330/libsensors/mlsdk/mllite/mlFIFO.c|FIFOSendGravity|1000 returning 26
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: FIFOSendGravity returned 26
    05-04 12:03:49.610 145 145 E Sensors : Fatal error: FIFOSendGyro returned 26
    05-04 12:03:49.610 145 145 V Sensors : MPLSensor::getFd returning -1
    05-04 12:03:49.610 145 145 V Sensors : MPLSensor::getAccelFd returning -1
    05-04 12:03:49.610 145 145 V Sensors : MPLSensor::getTimerFd returning 34

    (the sensor does not work at all when this condition is present
    and must be reset by pressing the switch in the pinhole)
    [ 05-04 06:51:48.520 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.570 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.620 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.670 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.680 1329:0x531 D/TestLog ]
    [ 05-04 06:51:48.720 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.780 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)
    [ 05-04 06:51:48.780 1329:0x533 D/dalvikvm ]
    GC_CONCURRENT freed 934K, 12% free 8123K/9159K, paused 2ms+7ms
    [ 05-04 06:51:48.810 1329:0x531 D/TestLog ]
    [ 05-04 06:51:48.830 141:0x99 E/Sensors ]
    MLUpdateData error (code 26)

    (the errors resume when the switch is again unlocked)
    [ 05-04 06:51:48.860 141:0x98 V/Sensors ]
    handle : 14 en: 0 mEnabled:00004000
    [ 05-04 06:51:48.860 141:0x98 V/Sensors ]
    sensor state change what=14
    [ 05-04 06:51:48.860 141:0x98 V/Sensors ]
    enabled_sensors: 0 dmp_started: 1
    [ 05-04 06:51:48.860 141:0x98 V/Sensors ]
    Stopping DMP
    [ 05-04 06:51:48.860 141:0x98 E/MPL-mlstates ]
    Error : illegal state transition from ML_STATE_SERIAL_CLOSED to ML_STATE_DMP_OPENED
    [ 05-04 06:51:48.860 141:0x98 E/MPL-dmp ]
    vendor/invensense/Invensense330/libsensors/mlsdk/mllite/mldmp.c|MLDmpStop|161 returning 25
    [ 05-04 06:51:48.860 141:0x98 E/Sensors ]
    error: unable to stop DMP (retcode = 25)
    [ 05-04 06:51:49.260 1329:0x544 D/PersistentEventStore/putEvent ]
    Row ID: 319, Event ID: 319

    I/dalvikvm( 82): System server process 141 has been created
    I/Zygote ( 82): Accepting command socket connections
    E/BatteryService( 141): usbOnlinePath not found
    I/sysproc ( 141): Entered system_init()
    I/sysproc ( 141): ServiceManager: 0x163da10
    D/SensorService( 141): nuSensorService starting...
    V/Sensors ( 141): sysapi object at 0x59414a1c
    V/Sensors ( 141): sysapi getBiases func at 0x5940f76d
    I/MPL-mlsl( 141): MLSLSerialOpen: /dev/mpu
    I/ ( 141): mpu3050_suspend: suspending sensors to 0000
    I/ ( 141): mpu3050_suspend: Will resume next to 03ff
    D/MPL-storeload( 141): 00(00) 01(00) 02(00) 03(24)
    D/MPL-storeload( 141): 04(00) 05(05) 06(ce) 07(1a)
    D/MPL-storeload( 141): 08(00) 09(00) 10(7c) 11(ff)
    D/MPL-storeload( 141): 12(00) 13(00) 14(ab) 15(df)
    D/MPL-storeload( 141): 16(ff) 17(ff) 18(15) 19(a1)
    D/MPL-storeload( 141): 20(ff) 21(ff) 22(f9) 23(68)
    D/MPL-storeload( 141): 24(ff) 25(ff) 26(f6) 27(ec)
    D/MPL-storeload( 141): 28(ff) 29(ff) 30(f4) 31(28)
    D/MPL-storeload( 141): 32(b5) 33(42) 34(79) 35(df)
    V/Sensors ( 141): MPLSensor::getFd returning 34
    V/Sensors ( 141): MPLSensor::getAccelFd returning 35
    V/Sensors ( 141): MPLSensor::getTimerFd returning 36

  2. gary712

    gary712 New Member

    The problem appears complicated so I'm not sure if this is a work around, but here is an observation. I installed AutoRotate Switch and my a500 started to auto rotate again.
    tansaku, idroids and Mrhelper like this.
  3. Mrhelper

    Mrhelper Well-Known Member

    Thanks so much for the information. I agree that this is complicated. There are numerous reports of similar symptoms, and there may be multiple causes. It is difficult to sort out whether problems are caused by certain apps, user behavior in some cases, and/or the apparent ICS bug I wrote about in this tip.

    Your problem appears to have a different cause than what I described in this tip, because the Autorotate Switch app from Market does not clear the rolling error condition -- i.e., 20 sensor errors per second accompanied by numerous system wide performance related problems. It does mitigate the error condition when used to lock the screen orientation though, just as the a500 screen orientation lock switch does. The Autorotate Switch app appears to merely lock and unlock automatic screen rotation just like the Iconia a500 switch near the volume control. It locks/unlocks auto rotation regardless of the a500 physical switch position, so if you were having a problem with auto rotation, where it was stuck in portrait or landscape mode, and the app fixed it, then I'm wondering if there was/is some problem with the switch on your unit. You may want to test that switch if you have not done so recently. Alternately, you may have yet another app that is changing the global settings for the screen rotation lock, and this one somehow overrides that one ...or something like that. I tested the Autorotate Switch app on my a500 while the accelerometer sensor error condition had been triggered. It did not clear the condition, nor restore normal sensor operation as required for automatic screen orientation. Only the hardware reset (pinhole) appears to clear that. It did pause and resume the flow of errors though, just like the physical switch on the unit does.
  4. gary712

    gary712 New Member

    Thanks for the response. The switch seems to be working fine. If auto rotate fail again I'll post an update.
  5. cryptonym

    cryptonym New Member

    I'm a noob here and it won't let me post a link until I say hi. So "HI".
  6. cryptonym

    cryptonym New Member

    Mrhelper likes this.
  7. Mrhelper

    Mrhelper Well-Known Member

    The problem described in my post above appears to be a problem that is first detected in Sensors driver init code. The first problem I see in the logs is a failure in subscribing to an InvenSense MPU device IRQ. After that occurs, it appears that all subsequent MPL calls for the device return error code 26. MLUpdateData error (code 26) messages are continuously written to the log every 50ms. This persists until I take a safety pin (which I now keep handy) and press the hardware reset switch. I've found nothing else to clear the condition after it is triggered. It does not happen with every boot, nor every power up, but it does trigger at power up only. If not the "sensors" driver initialization errors never occur, then all sensors work normally, and indefinitely, until future power down/up cycle happens to trigger the problem.

    The obvious symptoms when this happens are the loss of all motion sensors, affecting auto screen rotation, etc., which is accompanied by the many MLUpdateData errors streaming at 20/second into the log.

    I looked at the patch .zip file, and it does appear to contain "sensors" driver files. Have you seen any details about the problem that this patch is designed to fix? It would sure be nice to know if that solution will fix this problem. Thank you so much for the post.
  8. cryptonym

    cryptonym New Member

    More pieces to the puzzle.

    I just downloaded and installed Acer_AV041_A500_1.041.00_WW_CUS1 (very close to stock OTA, but rooted) over at XDA and applied it over the stock OTA I had received from Acer directly, Acer_AV041_A500_RV05RC01_PA_CUS1.

    Under Acer_AV041_A500_1.041.00_WW_CUS1 screen rotation (and the error 26's) would not clear. I could not get the rotation to work at all, even with multiple reboots, and hard (pinhole) resets.

    I restored to Acer_AV041_A500_RV05RC01_PA_CUS1 and rotation is back to it's unstable self, but at least a pinhole reset will clear it.
    Mrhelper likes this.
  9. Mrhelper

    Mrhelper Well-Known Member

    I've udpated my original post above with important information about the MPU init problem. In short, it appears to occur on the stock a500 ICS build, and mostly after short power down/up cycles. I'd be interested to hear if this works for others. Thanks.
  10. idroids

    idroids New Member

    gary712 you're a %&$@ing genius! :)

    Install free AutoRotate Switch app.
    Click on the app to switch ON auto-rotate.
    Turn the A500 off.
    Turn the A500 on.
    Auto-rotation works perfectly!

  11. gary712

    gary712 New Member

    The lost of auto-rotate returned with AutoRotate Switch installed, as mrhelper suggested it would. Hard resets did not fix the problem until I disable all but the standard keyboard input, then did a hard reset. I'm wondering if the problem is related to the 2 keyboards installed. I assume they are loaded during the boot phase. The key boards are TouchPal and Hacker's

    Disclaimer: I'm not even close to being knowledgeable in what the problem actually is. I'm only reporting my experiences. Maybe it will help.
    Mrhelper likes this.
  12. sgleon

    sgleon Member

    this is killing me, my kids can't play his racing games on the tablet either cause the accelerometer either/or gyroscope are not working and you cant steering the race car.
    This blows, i can't believe Acer is not fixing this.
  13. sgleon

    sgleon Member

    can i go back to Honeycomb?
  14. Mrhelper

    Mrhelper Well-Known Member

    If you still have warranty time remaining, and you can't clear the problem with the pinhole reset, then send it back and they should replace it. I would be remiss if I did not remind you at this point to make sure that the screen rotation lock switch is slid all the way left. I'm guessing you are already aware of that though because you responded to this particular post.

    As of today (6-19-2012), the Acer support centers appear to have no awareness of this problem. I grilled one of the chat support people about this today, and nothing.... not a clue.

    I asked if she could tell me when the next OS fix patch for the a500 was planned, and she had no information about that either. When I explained the screen rotation issues, I got the response I expected, which is apparently the typical response to any issue they don't understand -- i.e., send the unit in for repair service. I do not plan to send mine in for this problem because I can go for nearly a week without seeing it, and then I'll see it every day for a few days. I suspect that they would hit the reset which clears the condition on my system, and then they would just send it back. It's not worth my time go through all of that for such a slim chance of success.

    If the problem does not clear at all on yours, then if you send it in for repair they should see that and will likely replace it.

    If you have no remaining warranty, I may be able to direct you to a solution that worked for another a500 owner, but it does involve flashing an alternate ROM. You can use that method to go back to Honeycomb, or use a Honeycomb bootloader with one of the custom ICS ROMs to eliminate the problem.

    Note that this also happens with custom ICS ROMs when paried with ICS bootloaders, and some custom ROMs behave worse than stock ICS for this particular problem.
    sgleon likes this.
  15. sgleon

    sgleon Member

    Big thanks Mrhelper for all the work you have done on this issue and keeping all of us up to date. My warranty is over, so i am screwed until there is a fix.
    I did a software reset (erase all my apps and gmail account). No Help.
    I did the hardware reset you suggested, with the paperclip, the tablet reboots after in hit the pin hole. Still no help.
    The screen lock, i know how to work it.
    Is the screen rotate and the video games (steering cars or flying airplanes) not working the same issue or is it two sensors not working on my tablet?

    I also had a chat with Acer tech support:

    Well the Tele # he gave me is for Gateway, what BS!

    Status: Disconnected
    Chandrasekar M: Hi, my name is Chandrasekar M. How may I help you?
    Gunnar Leon: My Acer A500 has a issue with the AutoRotate
    Gunnar Leon: I tried a reset
    Chandrasekar M: Okay.
    Gunnar Leon: and the software reset and hardware reset
    Gunnar Leon: did not help
    Gunnar Leon: it is now useless for games
    Chandrasekar M: Can you elaborate the issue?
    Gunnar Leon: rotation problem and accelerometer not working
    Gunnar Leon: the screen gets locked
    Gunnar Leon: won't rotate
    Chandrasekar M: I understand that the tablet is not able to rotate the screen and accelerometer not working.
    Gunnar Leon: ok
    Gunnar Leon: thankas
    Gunnar Leon: plus is lots of people are having the issue ice cream sandwich bug on a500
    Chandrasekar M: I will do my best to fix the issue, Gunnar.
    Gunnar Leon: once i upgraded to ICS it happened
    Chandrasekar M: May I know the exact date of purchase?
    Gunnar Leon: 7-28-2011
    Gunnar Leon: did you see the link, this is a big issue for most people
    Chandrasekar M: Thank you for the information.
    Chandrasekar M: Yes, I saw the link.
    Gunnar Leon: can i downgrade to honeycomb?
    Chandrasekar M: I will check that for you.
    Chandrasekar M: May I place the chat on hold for 3 minutes, while I check and provide you the information?
    Gunnar Leon: neer had an issue in Honeycomb
    Gunnar Leon: thanks!
    Chandrasekar M: Thank you for being on hold.

    Gunnar Leon: thank you for helping me
    Chandrasekar M: Gunnar, did you check the touch screen lock button, whether it is on or not?
    Gunnar Leon: yes many times
    Chandrasekar M: It is on right.
    Gunnar Leon: yes, trust me
    Chandrasekar M: Okay.
    Chandrasekar M: May I place the chat on hold for another 3 minutes, while I search for you?
    Gunnar Leon: yes, remember I know there is no known fix, cause other users have call Acer, so i am happy to downgrade to Honeycomb
    Chandrasekar M: Thank you for being on hold.
    Chandrasekar M: Gunnar, we have to disable the touch screen lock button to rotate the screen.
    Gunnar Leon: i just did a factory reset and right away it does not work,
    Gunnar Leon: i did not change any settings
    Chandrasekar M: Gunnar, try to disable the touch screen lock button and check the screen.
    Gunnar Leon: the button in the side by the volume?
    Chandrasekar M: Yes.
    Gunnar Leon: screen lock button by the volume
    Chandrasekar M: Yes, that is button.
    Gunnar Leon: like i said i have tried the button hundreds of time
    Gunnar Leon: times, but i will try again for you
    Gunnar Leon: ok no help
    Chandrasekar M: Thank you.
    Gunnar Leon: please i know there is not fix
    Gunnar Leon: i need downgrade instructions
    Chandrasekar M: Okay. I will check that for you.
    Chandrasekar M: Gunnar, to resolve this issue you need the send the tablet for repair.
    Gunnar Leon: how about an OS downgrade path?
    Chandrasekar M: Unfortunately we don't have any steps to downgrade the operating system.
    Chandrasekar M: We have service the tablet to change the operating system.
    Gunnar Leon: can you give me a telephone # to call for tablet service
    Chandrasekar M: I will help you with our phone support number. They will assist you.
    Gunnar Leon: ok
    Chandrasekar M: Please call 8665393901 for USA.
    Chandrasekar M: Gunnar, to conclude we have provided the information and this should help you fix the issue. If there are no additional questions on this topic, I will close the chat session.
    Chandrasekar M: Thank you for contacting Acer support.
    Chandrasekar M has disconnected.
  16. sgleon

    sgleon Member

    i really don't want to mess with the OS on this Tablet, but it seems like i don't have a choice . If you can direct me the the easiest way of installing a new bootloader and ROM that would work, many thanks!
  17. sgleon

    sgleon Member

    I called this # 800-845-2237 (Acer) and they said my tablet was still covered, so i am sending it back.
    But the tech said that people need to call about the issue, if we want Acer to work on fixing the bug.
    He said that there have not been a lot of calls so far for the issue.

    he also said that the fix is installing ICS (clean install).

    I asked if they can post for download the OS and instructions for others that have the issue and are out of warranty can fix it them selves.
    His rely again was, "you guys need to call and complain for that to happen"

    Pickup the phone guys.
    And thanks for everyone that helped me with all the info you guys posted.
  18. Wilsr

    Wilsr Member

    Same problem (amongst others) after ICS "upgrade". (My quotes)

    Although *some* apps will change the orientation when they start, when I quit them the autorotation will not work.

    I have done the pinhole reset, also the factory reset but with no change.

    Acer are sending me a voucher to return the A500 for "repair" although exactly what can be done about a firmware bug I don't know.

    Although many seem to have gone to ICS without problems, and given that once there you can't go "back", I would think hard and long before "upgrading" if I had to do it again.

  19. AndiPi

    AndiPi New Member

    Hi all,

    first of all, a big thank you to Mrhelper for his analysis. I am facing the same problems on my TPrime. Same symptoms, most likely same root cause. And btw, same problem with Asus support.

    If this error appears on more than one ICS device what's then the conclusion? Should we start to fire against Google rather than Asus and Acer?
  20. Mrhelper

    Mrhelper Well-Known Member

    Thanks much for the post. This is very interesting. Did you see the error code 26s in the log? Does it clear temporarily with a hardware reset? If you see the error code 26s and cannot clear the condition, as well as possibly having the same cause, it is also possible that it is caused by some other issue, such as a defective sensor chip.

    I've seen the question of Google responsibility asked a few times for similar issues, and the answer is apparently no. What Google provides is very abstract relative to specific hardware. This does not appear to be a problem with Android, but a problem of implementing an Android device with certain hardware components. This problem is a consequence of hardware timing relative to the Linux kernel boot sequence, and timing of that sequence. That is something that only the device manufacturer can implement and manage. Asus and Acer use much of the same hardware, including the same CPUs and sensor chips (I recall). It is my understanding that Google does not specify that an Android device manufacturer use one hardware vendor vs another, nor does Google produce the hardware drivers. This is a problem that was created and delivered by the tablet vendor(s) and possibly contributed to by the sensor chip vendor.
  21. Wilsr

    Wilsr Member

    Mr Helper, first thanks for the input.

    I think this problem is indicative of a more fundamental problem with open source-type systems: the fragmentation of various builds by different people/companies. It's very apparent with Linux - hundreds of distros, each with its own updates and bugs

    The Unique Selling Proposition of open source (free, multiple inputs) is its basic fault too.
  22. dbldipp

    dbldipp Well-Known Member

    I got tired of all the not working correctly features of ICS and did a go back to HC. Mrhelper helped but I ultimately had to have a family member save my behind because when I tried doing it I bricked my tablet. So if you want to go back, yes you can. But be forwarned, it's not a walk in the park and you could end up with a brick!
    We need a thread on here with exact instructions for those who want to go back and how to do it safely.
  23. RMinMN

    RMinMN Active Member

    I remember having this issue with Windows 98. On my computer Windows 98 would crash every so often and need to be reinstalled. With my system, all peripheral boards needed to be removed, Win98 reinstalled, then the boards inserted and the software for each board had to be installed, with a reboot for each board. If you installed the video driver first the sound card would never work. The maturity of Android may still be at that level.
    jimburn69 likes this.
  24. stridermt2k

    stridermt2k Well-Known Member

    I've never been into hacking these things at the ROM level. It's just no fun at all for me.
    I've decided to check out a couple of the Tegra 3 offerings and give mine to a family member to wrestle with.
  25. Wilsr

    Wilsr Member

    Those who have had screen rotation go phut after the ICS "upgrade" may be interested:

    I returned my Iconia A500 to Acer Australia last week, it was returned today - excellent turnaround. They identified problems with the motherboard and "the pointing device" - whatever that is?

    They replaced the MB, and all works as it should.

    This indicates to me that *some* of the Iconias out there have something in the firmware that has made the rotation initialisation unworkable, which is why only some of us have apparently been affected.

    Well done anyway, Acer, for the repair. Just as well though that I was within the 12 months' warranty, even though I assume the problem originated with their firmware/upgrade.

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