Re: [RFC PATCH] drivers: power: Add watchdog timer to catch driverswhich lockup during suspend.

From: Greg Kroah-Hartman
Date: Tue Apr 30 2013 - 19:30:41 EST

On Tue, Apr 30, 2013 at 03:28:33PM -0700, Zoran Markovic wrote:
> From: Benoit Goby <benoit@xxxxxxxxxxx>
> Below is a patch from android kernel that detects a driver suspend
> lockup and captures dump in the kernel log. Please review and provide
> comments.

There's this really cool thing called a watchdog driver that does stuff
like this :)

> Rather than hard-lock the kernel, dump the suspend thread stack and
> BUG() when a driver takes too long to suspend. The timeout is set to
> 12 seconds to be longer than the usbhid 10 second timeout.
> Exclude from the watchdog the time spent waiting for children that
> are resumed asynchronously and time every device, whether or not they
> resumed synchronously.

No, don't add a driver-core-only timer, use the existing watchdog timers
if you are worried about the kernel locking up.


greg k-h
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