Opened 11 years ago

Closed 11 years ago

Last modified 10 years ago

#6561 closed defect (invalid)

video sync using DRM vblank on VIA cn400 hardware is broken starting with the 2.6.28 kernel.

Reported by: pebender@… Owned by: Isaac Richards
Priority: minor Milestone: unknown
Component: MythTV - Video Playback Version: 0.21-fixes
Severity: low Keywords:
Cc: Ticket locked: no

Description

It appears that changes in the DRM code introduced in the 2.6.28 kernel broke video sync using DRM vblank on VIA cn400 hardware. By default, with the 2.6.28.10, 2.6.29.3 and 2.6.30-rc6 kernels, video playback on my VIA SP8000E is completely unwatchable due to stutters and stalls. However, if I disable the use of DRM vblank either by renaming /dev/dri/card0 (using udev rules) or by commenting out the DRM video sync test in mythtv/libs/libmythtv/vsync.cpp, then MythTV uses usleep and everything works fine.

Change History (3)

comment:1 Changed 11 years ago by danielk

Resolution: invalid
Status: newclosed

Bug is upstream in Linux kernel.

comment:2 Changed 11 years ago by pebender@…

Thank you for the quick response.

Do you happen to have a pointer to a fix (or where it is reported as a bug?

I would love to be able to patch the MiniMyth? kernel. However, I have not been unable to find anything related to the problem on kernel mailing list <http://lkml.org>, in the kernel bug tracker <http://bugzilla.kernel.org/>, in main kernel git tree <http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git> or in main drm git tree <http://cgit.freedesktop.org/mesa/drm/>.

comment:3 Changed 10 years ago by bam

Here is the patch:
DRM: Fix VBlank IRQ on VIA hardware http://www.mail-archive.com/dri-devel@lists.sourceforge.net/msg41318.html

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