[Mesa-dev] [PATCH 0/3] Support for Android RGBX/RGBA formats

[Emil Velikov]

On 24 April 2016 at 14:20, Marek Olšák <maraeo at gmail.com> wrote:
> On Sun, Apr 24, 2016 at 3:09 PM, Marek Olšák <maraeo at gmail.com> wrote:
>> On Sun, Apr 24, 2016 at 2:16 PM, Marek Olšák <maraeo at gmail.com> wrote:
>>> On Fri, Apr 22, 2016 at 12:41 PM, Chih-Wei Huang
>>> <cwhuang at android-x86.org> wrote:
>>>> 2016-04-21 21:42 GMT+08:00 Emil Velikov <emil.l.velikov at gmail.com>:
>>>>>
>>>>> On 19 April 2016 at 20:38, Rob Herring <robh at kernel.org> wrote:
>>>>>> The RGBX/RGBA pixel formats used in the Android EGL don't get configs
>>>>>> created due to the missing formats in the DRI state tracker. This series
>>>>>> adds the necessary formats for configs and DRI images. Support in GBM is
>>>>>> also added as it will be needed soon for Android.
>>>>>>
>>>>>> AFAICT, this has been a long standing bug in Android-x86 which was
>>>>>> worked around with the patch "GLSurfaceView: Be less picky about
>>>>>> EGLConfig alpha sizes". With this series, this patch is no longer needed
>>>>>> and several other bugs like wallpaper not getting displayed are fixed.
>>>>>>
>>>>> In the past similar changes has caused unexpected bugs and/or pert regressions.
>>>>>
>>>>> Although I doubt we'll notice them with the patches on the ML, thus
>>>>> I've pushed the lot to get some wider testing.
>>>>>  Please keep an eye for fires ;-)
>>>>
>>>> Could these be back-ported to 11.2?
>>>
>>> DEFINITELY NOT.
>>>
>>> It's too risky and it has already broken GLX.
>>
>> OK so the problem is libGL ignores the red/green/blue mask, therefore
>> it doesn't distinguish between BGRA and RGBA. Also, DRI always assumes
>> it's BGRA on the X server side. This patch series also ignores the
>> red/green/blue mask for imported buffers. That's why DRI2 mostly
>> works. I haven't tested DRI3.
>>
>> libGL could be fixed not to expose RGBA visuals, but that's
>> insufficient, because Mesa drivers must be loadable by older libGL
>> too.
>>
>> The bottom line is st/dri can't expose RGBA, because it would break
>> Mesa with old libGL.
>>
Speaking of which... I while back I was asking/proposing that we
deprecate 'too old' loader (libGL) <> dri modules combos. Something
like ~3 year difference came to mind (functionality based). Do we have
(m)any people who explicitly test dri module from today and libGL form
5-6, 10 years ago ?

How do you feel on the topic ?

>> Unless you guys come up with a solution, I'll have to revert the st/dri change.
>
> FYI, I've decided to revert the st/dri commit now to fix the KDE
> issue.
>
Ack. Thanks for looking into it Marek !

Emil