[Bug 654876] Re: [Sandybridge] Attempting to use Xv textured video hangs the system.

[Martin Pitt]

Do we also have a non-Sandybridge i830 based chipset for testing
anywhere, so that we can confirm that Xv still works on those?

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[Sandybridge] Attempting to use Xv textured video hangs the system.
https://bugs.launchpad.net/bugs/654876
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Status in X.org xf86-video-intel: Confirmed
Status in “xserver-xorg-video-intel” package in Ubuntu: Fix Committed
Status in “xserver-xorg-video-intel” source package in Maverick: Fix Committed

Bug description:
--- SRU JUSTIFICATION NOTES ---

IMPACT: Sandy Bridge machines (with generation 6 intel GPUs) do not have code in the driver to handle Xv acceleration, but due to the way its coded it advertises that it works and attempts to use a generic GM45 generation code path for it which hangs the system 100% of the time. This confuses gstreamer which does auto detection and every app that plays back video with it will hang the system unless Xv is forcibly disabled.

RESOLUTION: Disable Xv only on this generation of devices by adding an XVideo option to the intel driver that only disables it on generation 6 devices. The option was universally enabled previously.

TEST CASE:
1) Boot ubuntu maverick on a Sandy Bridge machine
2) Launch gstreamer-properties
3) Go to the video tab, under default output press "Test"
4) System hangs without this fix. Switching the output to "X Window System (No Xv)" works correctly.

REGRESSION POTENTIAL: Extremely low, this only changes the behavior for devices that match the IS_GEN6 macro which only contains Sandy Bridge devices.

SRU PATCH PROPOSALS:
https://bugs.edge.launchpad.net/ubuntu/+source/xserver-xorg-video-intel/+bug/654876/+attachment/1699567/+files/xserver-xorg-video-intel_2.12.0-1ubuntu5.1.debdiff

--- ORIGINAL DESCRIPTION ---

Binary package hint: xserver-xorg-video-intel

xserver-xorg-video-intel does not have support for Sandybridge Xv video acceleration, but it advertises support and attempting to use it is causing a system hang. Given that these devices will be released before 11.04 is released, I believe it would be in our best interest to disable Xv for Maverick for a better user experience. The change only affects these specific devices (covered by the IS_GEN6 macro) so the regression potential is extremely low.

Upstream addressed this issue in this commit:
http://cgit.freedesktop.org/xorg/driver/xf86-video-intel/commit/?id=8784c4f5a1524fb979b00c7ce7981cbc1dcf0ec0

author	Chris Wilson <chris at chris-wilson.co.uk>	2010-10-01 20:40:36 (GMT)
committer	 Chris Wilson <chris at chris-wilson.co.uk>	2010-10-01 20:45:15 (GMT)
commit	8784c4f5a1524fb979b00c7ce7981cbc1dcf0ec0
tree	d73f10e7631195c2ecb70d87aa7f3ba00da93e09
parent	345c963e443ec325f1ff530512a356ddb318ff70

video: Disable TextureAdaptor for Sandybridge
The acceleration code does not yet exist, so we try to use gen4 shaders
which hangs the chip and makes everybody upset. Disable it until such a
time as support is written for Sandybridge XVideo.

Reported-by: Matthias Hopf <mhopf at suse.de>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=30500
Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>

Patch will follow soon and has been tested by me on 2 sandybridge machines to verify that desktop applications that autodetect Xv support no longer crash the system (cheese, totem visualizations, rhythmbox visualizer).