[PATCH xserver] modesetting: Fix page flipping under DRI 3.2.

[Mario Kleiner]

Btw. another new problem, which i haven't had time to track down at
all is that desktop composition under EGL seems to be totally broken.
Tested on KUbuntu 16.0.4 LTS with xserver master + mesa master last
thursday with whatever KDE Plasma 5 version ships with 16.04.
Compositing with XRender accel or GLX + OpenGL 2/3 works fine. Could
be modesetting, or glamor, or mesa.

I get sometimes black screen, or sometimes massive corruption with
pixel trash like if it displays random buffer contents from
uninitialized buffers under modesetting-ddx + DRI3, on all kms
drivers. Can anybody confirm this?
-mario


On Tue, Apr 3, 2018 at 4:47 PM, Daniel Stone <daniel at fooishbar.org> wrote:
> Hi Mario,
>
> On 3 April 2018 at 15:44, Mario Kleiner <mario.kleiner.de at gmail.com> wrote:
>> Those are fine according to my testing, they fix mode-setting under
>> both depth24 and 30.
>>
>> However as testing shows, still not sufficient for pageflipping if the
>> kms driver doesn't support full atomic (as tested on radeon-kms, and
>> as well under nouveau-kms without the nouveau.atomic=1 kernel boot
>> parameter). Even with atomic (nouveau.atomic=1, or intel-kms)
>> pageflipping doesn't get used when it should be if the driver exposes
>> num_modifiers==0, e.g., Intel Ivybridge under Linux 4.13 (whereas
>> Linux 4.15-something was fine under Intel).
>>
>> The following snippet made pageflipping work on radeon-kms, intel-kms
>> (Tested Linux 4.13 and some slightly outdated drm-next), nouveau-kms
>> with/without nouveau.atomic=1 module parameter. I can turn it into a
>> proper patch later today:
>
> Thanks for tracking this down! That looks like the right thing to do,
> modulo the obvious debug lines.
>
> Cheers,
> Daniel