Radeon Page-Flipping Patches Come About

[phoronix]

Phoronix: Radeon Page-Flipping Patches Come About

Since the Linux 2.6.32 kernel there has been the KMS page-flipping ioctl and it's been hooked into the Intel DRM driver for providing tear-free updating of the screen by low-latency page-flipping. This KMS page-flipping ioctl is also used by Wayland. Since late October there's also been Nouveau patches for page-flipping, but now patches have finally emerged for bringing this support to the Radeon DRM driver...

http://www.phoronix.com/vr.php?view=ODcyMA

[d2kx]

Ubuntu 11.04 is going to use Linux 2.6.38 anyway, so that's ok for me

[agd5f]

I send out updated patches later which fix the remaining issues with pre-6xx asics. pageflipping works with tiling on pre-6xx fine. It's just 6xx+ tiling that is problematic, but should be fixable without too much trouble.

[pejakm]

Those are great news, indeed.

[monraaf]

Doesn't seem to work here on my Evergreen with latest drm-radeon-testing kernel + these patches. Displays corrupted image when going fullscreen with flash player or using glxgears -fullscreen. And sometimes corrupts other parts of desktop as well.

radeon_dri2_schedule_flip:571 fevent[0x943a2d0]
radeon_dri2_flip_event_handler:927 fevent[0x943a2d0] width 1680 pitch 7168 (/4 1792)

[xeros]

What does it mean? Is it for removing tearing completely or something else, too? Will it bring gain or drop of FPS or add some new needed extensions?

[agd5f]

Doesn't seem to work here on my Evergreen with latest drm-radeon-testing kernel + these patches. Displays corrupted image when going fullscreen with flash player or using glxgears -fullscreen. And sometimes corrupts other parts of desktop as well.

radeon_dri2_schedule_flip:571 fevent[0x943a2d0]
radeon_dri2_flip_event_handler:927 fevent[0x943a2d0] width 1680 pitch 7168 (/4 1792)

Try the newer patches I posted later. here:
http://people.freedesktop.org/~agd5f/pflip/
for your convenience.

[agd5f]

What does it mean? Is it for removing tearing completely or something else, too? Will it bring gain or drop of FPS or add some new needed extensions?

Instead of blitting (copying) the back buffer to the front buffer on a GL buffer swap, the front/back buffer pointers are swapped so the display hw ends up pointed at the back buffer and vice versa. It should be faster then blitting as it avoids the additional copy and the engine isn't stalled to avoid tearing when doing the copy. It also saves memory bandwidth as there's no additional copy.

[agd5f]

I also added a patch to fix tiling + flipping on 6xx+ (5xx and older were already supported).

[gentoofu]

With all the patches that recently came in, is there still a chance for this to be merged in for 2.6.37?