DMA-BUF Cross-Device Synchronization Still Baking

[phoronix]

Phoronix: DMA-BUF Cross-Device Synchronization Still Baking

One of the features that multi-GPU (Optimus/PRIME) owners and other DMA_BUF-using Linux users have been waiting on is cross-device synchronization support. Patches are still flowing for this missing feature and with some luck maybe we will finally see it ready for the Linux 3.15 kernel...

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

[sarmad]

I can't wait for this to be implemented. I am sick of tearing with DRI_PRIME.

[mannerov]

I can't wait for this to be implemented. I am sick of tearing with DRI_PRIME.

Even if the support is merged (and the patches on the mailing list lack yet the patches to implement it for the intel, radeon and nouveau drivers),
there will still be glitches with X DRI2, because when DRI_PRIME is set, it disables vsync.

[mannerov]

Even if the support is merged (and the patches on the mailing list lack yet the patches to implement it for the intel, radeon and nouveau drivers),
there will still be glitches with X DRI2, because when DRI_PRIME is set, it disables vsync.

I wanted to say tearings, not glitches (with the patches, there shouldn't be any glitches)

[sarmad]

Even if the support is merged (and the patches on the mailing list lack yet the patches to implement it for the intel, radeon and nouveau drivers),
there will still be glitches with X DRI2, because when DRI_PRIME is set, it disables vsync.

That sucks. Oh well, I guess we'll have to wait for Wayland. Hopefully Wayland will be tear free wether with PRIME or not.

[Ericg]

That sucks. Oh well, I guess we'll have to wait for Wayland. Hopefully Wayland will be tear free wether with PRIME or not.

He said X DRI2 had tearing. DRI3 -might- not. I can't get a solid yes or no from googling.

[mannerov]

He said X DRI2 had tearing. DRI3 -might- not. I can't get a solid yes or no from googling.

Depends how DRI_PRIME is implemented for DRI3.
For the moment it hasn't been implemented.

But now I think of it, the patches might get rid of tearings with DRI2 with an X compositor doing full screen refreshes synced with vsync.

[liam]

I wanted to say tearings, not glitches (with the patches, there shouldn't be any glitches)

What's the difference?

[Mat2]

Hello,
Is there any progress on this?
I have seen virtually nothing on the mailing list.

[mannerov]

There's still discussions on the best way to handle issues with one gpu to not crash the other one.