Re: freeze on OMAP4460, timestamps jumping

2015-09-09 Thread Kunal Singh
Hi,

In continuation to my earlier email, here are the kernel logs
[last_kmsg on watchdog reboot]
http://paste.ubuntu.com/12319445/
http://paste.ubuntu.com/12319449/
http://paste.ubuntu.com/12319453/
http://paste.ubuntu.com/12319460/

One thought we had was that may be sudden time-stamp jump is causing
the crash. So, we built kernel with CONFIG_NO_HZ. But that didn't
help.
We have also tried kernel image built with CONFIG_PRINTK_TIME &
CONFIG_HAVE_UNSTABLE_SCHED_CLOCK and options. Still we run in to
identical problems.

We have total three product variants using similar platform. The
problem occurs only on one of the three products.
Also, on the failing product, some devices are stable [have never
failed the tests]. Out of failing boards, some boards have higher
failure frequency. Could the problem be related to Power/Clock
management? Is there any particular item we can check w.r.t. hardware.

Regards,
Kunal

On 9 September 2015 at 13:50, Kunal Singh  wrote:
> Hi,
>
> We have a OMAP4460 based platform running Android Jellybean. We have
> observed that OMAP can totally freeze at times, leading to watchdog
> reboot.
>
> There are two test cases which consistently reproduce the problem
> - Running Camera Preview
> - copying large files to eMMC.
>
> Both of the above test cases involve heavy DMA. So, we are suspecting
> that crash may be related to some DMA processing/logic.
>
> After the watchdog reboot, last_kmsg consistently show two things
> - A sudden jump in timestamps prior to crash
> - Unhandled Fault in the kernel logs. The fault type can vary, but
> it's mostly one of the following
>- Unhandled fault: imprecise external abort (0x1406)
>- Unhandled fault: external abort on non-linefetch (0x1008)
>
> From last_kmsg, the PC/LR is mostly at omap4_prm_inst_read_inst_reg
> and omap4_pwrdm_read_pwrst respectively. Sometimes at other places
> (e.g. sched_clock )
>
> Can someone suggest what might be causing this?
>
> Regards,
> Kunal



-- 

Kunal Singh
Embedded Systems Developer, BARTEC PIXAVI

Email:kunal.si...@bartec-pixavi.com
Mobile:+91 9818408590
Skype:kunalbangalore
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freeze on OMAP4460, timestamps jumping

2015-09-09 Thread Kunal Singh
Hi,

We have a OMAP4460 based platform running Android Jellybean. We have
observed that OMAP can totally freeze at times, leading to watchdog
reboot.

There are two test cases which consistently reproduce the problem
- Running Camera Preview
- copying large files to eMMC.

Both of the above test cases involve heavy DMA. So, we are suspecting
that crash may be related to some DMA processing/logic.

After the watchdog reboot, last_kmsg consistently show two things
- A sudden jump in timestamps prior to crash
- Unhandled Fault in the kernel logs. The fault type can vary, but
it's mostly one of the following
   - Unhandled fault: imprecise external abort (0x1406)
   - Unhandled fault: external abort on non-linefetch (0x1008)

>From last_kmsg, the PC/LR is mostly at omap4_prm_inst_read_inst_reg
and omap4_pwrdm_read_pwrst respectively. Sometimes at other places
(e.g. sched_clock )

Can someone suggest what might be causing this?

Regards,
Kunal
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