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From: Jani Nikula <jani.nikula@linux.intel.com>
To: Mario Kleiner <mario.kleiner.de@gmail.com>,
	intel-gfx <intel-gfx@lists.freedesktop.org>
Subject: Re: Breakage for Ironlake due to some watermarks changes in	Linux 4.0+?
Date: Fri, 15 May 2015 12:00:42 +0300	[thread overview]
Message-ID: <87wq0amczp.fsf@intel.com> (raw)
In-Reply-To: <55553BCC.3050609@gmail.com>

On Fri, 15 May 2015, Mario Kleiner <mario.kleiner.de@gmail.com> wrote:
> Hi all,
>
> since Linux 4.0 i experience some massive display flicker problem on my 
> Intel HD Ironlake mobile (2010 MacBookPro6,2) under Waylands reference 
> compositor Weston.
>
> - Only happens on Linux >= 4.0 on intel-kms with the Intel HD, not under 
> nouveau-kms with the discrete NVidia gpu. Strangely on Linux 4.1-rc it 
> happens all the time, whereas on Linux 4.0 it can work normally for 
> quite a while, but once the problem starts only a reboot can cure it.
>
> - Almost only happens on Weston, but only very rarely under the XServer. 
> VT switching from Weston to XOrg makes the problem disappear, switching 
> back to Weston and it starts again immediately.
>
> - Only happens if a hardware cursor is displayed - hiding the cursor 
> stops the flicker immediately, showing the cursor starts the flicker.
>
> - The drm and desktop is completely idle during this - drm.debug=15 
> shows no activity while this happens.
>
> Symptom:
>
> Up to the scanline where the cursor is located, the desktop image is 
> displayed, but jumps horizontally left and right by some random number 
> of pixels, maybe in the range 0 - 200 pixels with high frequency, making 
> the content unreadable. Starting with the scanline where scanout of the 
> cursor starts, the display goes blank, as if some display controller 
> fifo would underflow and the controller blanks the display in response. 
> Seems having to scanout the cursor plane in addition to the primary 
> plane is just enough to push it over some limit?
>
> I also see cpu and pch pipe a fifo underruns reported by the underflow 
> irq handlers.
>
> I saw there were many changes around Linux 4.0 in the kms driver wrt. 
> watermark calculations, so this might be related?

Please try http://patchwork.freedesktop.org/patch/49314 and report back.

BR,
Jani.

>
> thanks,
> -mario
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Jani Nikula, Intel Open Source Technology Center
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  reply	other threads:[~2015-05-15  9:02 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-05-15  0:20 Breakage for Ironlake due to some watermarks changes in Linux 4.0+? Mario Kleiner
2015-05-15  9:00 ` Jani Nikula [this message]
2015-05-19  4:38   ` Mario Kleiner
2015-05-19  7:38     ` Jani Nikula

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