linux-kernel - Re: Kernel stability on baytrail machines

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Message-ID: <7f521bff-0fbf-a2f4-e779-c9bc40c7cd84@feix.cz>
Date:	Tue, 19 Jul 2016 06:51:17 +0200
From:	Michal Feix <michal@...x.cz>
To:	Pavel Machek <pavel@....cz>
Cc:	Ezequiel Garcia <ezequiel@...guardiasur.com.ar>,
	One Thousand Gnomes <gnomes@...rguk.ukuu.org.uk>,
	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org,
	dri-devel@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org
Subject: Re: Kernel stability on baytrail machines

Dne 13.7.2016 v 12:48 Pavel Machek napsal(a)

>>>> Are there any updates on the status of this issue?
>>>>
>>>> The current bugzilla report [1] marks this as a power management
>>>> issue. However, many reports indicate that it would only freeze
>>>> when running X, so it's not completely clear if it's related to
>>>> the gfx driver too.
>>> Does
>>>
>>> "intel_idle.max_cstate=1"
>>>
>>> fix it for you?
>> Yes, it does.
>>> If you feel it is X-only problem, you may want to provide details
>>> about your graphics subsystem (DRM enabled? framebuffer only?) and
>>> probably cc.
>> It's not X-only problem. Happens even in console mode, which is KMS
>> switched during boot though.
>>> ...actually... you may want to verify if it happens in unaccelerated X.
>> As it happens even in console mode, is this relevant test?
> No, no need to test with X.
>
> Would it be possible to test in good old VGA mode?
For past few days I updated to 4.6.3 kernel and tested with X and 
without X, in console mode and no KMS. My machine is way more stable 
than with previous 4.5.* and 4.4.* kernels I tried.

With 4.6.3 kernel and X running, I had only one freeze during Firefox 
session with video playback. For the rest of two days of testing, no hang.

I was not able to hang the machine during another 2 days of testing with 
4.6.3 kernel and console mode with KMS disabled. It's fair to say, that 
stress testing of GFX is quite limited when running in console mode :-). 
I tried hard with mplayer with libcaca and with repeated kernel 
compilation task. No hang occured.

My conclussion is that 4.6.3 is surelly a huge improvement, compared to 
4.5 and 4.4. kernels regarding Bay trail stability issue.

Michal Feix