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

[Andreas Müller]

On Fri, Mar 30, 2018 at 4:41 PM, Daniel Stone <daniel at fooishbar.org> wrote:
> Hi Andreas,
>
> On 30 March 2018 at 15:18, Andreas Müller <schnitzeltony at gmail.com> wrote:
>> What happened: I build all images cross with Openembedded/Yocto. To
>> prepare next release there I updated my builds and that moved mesa
>> 17.1.7 -> 17.3.7. Since then all applications using GL/GLES (e.g
>> glmark2-es - tried others - same) complain with
>>
>> | Modifier 0x0 vs. tiling (0x700000000000001) mismatch
>>
>> and drawable region remains black.
>> There was some discussion on meta-raspberrypi mailing list and it
>> seems to happen to others too [1].
>>
>> I've attached a patch. That fixes glmark2-es and many others but e.g
>> on KDE desktop mouse pointer is just pixel dust so I think that my
>> (naive) approach only works around an issue caused somewhere else. To
>> ne honest my background understanding is poor but it seems that
>> modifier gets not properly for all cases.
>
> Odd. That happens when something has already allocated the buffer as a
> tiled buffer, but Mesa is being told that the buffer is linear. Are
> you able to get a backtrace from when this error happens? (Either set
> a breakpoint by hand, or just add 'uint32_t *crash = NULL; *crash =
> 1;' to force a segfault.)
>
> I could only find one place where this would happen, which is when
> using the old DRI2 interface with Gallium, but it really should be
> using DRI3 ... nonetheless, does the attached patch help at all?
>
> Cheers,
> Daniel
Hi Daniel,

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...

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?
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?

Cheers

Andreas