[Mesa-dev] VC4 not working for me with mesa 17.3.7

[Daniel Stone]

Hi Andreas,

On 31 March 2018 at 15:18, Andreas Müller <schnitzeltony at gmail.com> wrote:
> Thanks for prompt an VERY helpful support. I did:
>
> * Check my configure and found: --disable-dri3!
> * Tested your patch (with --disable-dri3) and as expected it fixes the issue
> * Found what causes --disable-dri3 - it came in by the Openembedded
> update mentioned in first email. FWIW: I use a fork for
> meta-raspberrypi - the original is not affected so I am the only one
> with this issue...

Glad to hear it!

> I have two questions related to dri2/your patch (sorry asking for more :)
>
> 1. Your patch fixes improper initialized variable. Do you think it is
> worth being applied?

Yes, definitely: I've sent it in now. It's sadly missed 17.3.8
(scheduled to be released about an hour ago), but hopefully we can get
it in for a 17.3.9, if we have one. Else it'll be in 18.0.1.

> 2. In the thread I mentioned in my first email Trevor mentioned that
> he has seen error message 'Modifier 0x0 vs. tiling(0x7000000000000001)
> mismatch' when trying to get chromium GLES accelerated. Maybe a stupid
> question but is it possible that applications running at X can ask for
> dri2 explicitly?

He said that only happened when using the system (rather than bundled)
libraries, which would presumably be using DRI2 by default. I've
submitted a bug to OE to ask them to enable DRI3 by default, but in
the meantime this Mesa fix should hopefully work anyway.

Cheers,
Daniel