Opened 11 years ago

Closed 11 years ago

Last modified 11 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


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, 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 <>, in the kernel bug tracker <>, in main kernel git tree <> or in main drm git tree <>.

comment:3 Changed 11 years ago by bam

Here is the patch:
DRM: Fix VBlank IRQ on VIA hardware

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