Re: commit 70fea60d888d caused s2ram regression with WD disk

[Takashi Iwai <tiwai@suse.de>]

At Mon, 15 Jun 2015 10:55:36 +0800,
Aaron Lu wrote:
> 
> Hi,
> 
> As explained by Takashi:
> "
> So this looks like the cause.  The recent kernel has a watchdog for
> async resume workers, and if it expires, it panics.  This explains why
> 3.12 worked; the watchdog was introduced since 3.13.
> 
> The timeout length is unfortunately fixed in Kconfig, set to 12 as
> default.  And this seems too short.  We should extend this to at least a
> minute, I suppose.  Also, it'd be better to be dynamically
> configuratble.
> "
> https://bugzilla.opensuse.org/show_bug.cgi?id=934397#c5
> 
> The upstream bug page is here:
> https://bugzilla.kernel.org/show_bug.cgi?id=91921
> Since Benoit isn't registered there, I write the email for discussion.

Thanks Aaron for starting a thread.

Below is a patch to make the default value a bit safer.

I can submit another patch to add a boot option to change the timeout
value, too, if anyone thinks it's worth.  Just let me know.


thanks,

Takashi

-- 8< --
From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] PM: Increase default DPM watchdog timeout to 60

Many harddisks (mostly WD ones) have firmware problems and take too
long, more than 10 seconds, to resume from suspend.  And this often
exceeds the default DPM watchdog timeout (12 seconds), resulting in a
kernel panic out of sudden.

Since most distros just take the default as is, we should give a bit
more safer value.  This patch increases the default value from 12
seconds to one minute, which has been confirmed to be long enough for
such problematic disks.

Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=91921
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 kernel/power/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/power/Kconfig b/kernel/power/Kconfig
index 7e01f78f0417..9e302315e33d 100644
--- a/kernel/power/Kconfig
+++ b/kernel/power/Kconfig
@@ -187,7 +187,7 @@ config DPM_WATCHDOG
 config DPM_WATCHDOG_TIMEOUT
 	int "Watchdog timeout in seconds"
 	range 1 120
-	default 12
+	default 60
 	depends on DPM_WATCHDOG
 
 config PM_TRACE
-- 
2.4.3