[waffle] [Piglit] [ANNOUNCE] waffle-1.2.2

[Marek Olšák]

On Wed, Nov 28, 2012 at 8:42 PM, Chad Versace
<chad.versace at linux.intel.com> wrote:
> On 11/28/2012 10:40 AM, Marek Olšák wrote:
>> On Wed, Nov 28, 2012 at 7:26 PM, Chad Versace
>> <chad.versace at linux.intel.com> wrote:
>>> On 11/27/2012 07:47 PM, Marek Olšák wrote:
>>>> HI Chad,
>>>>
>>>> FYI, the core GL support in the GLX backend of waffle and/or piglit
>>>> seems to be broken. All piglit tests that specify the core GL version
>>>> and are run on a driver which cannot create a core GL context (that is
>>>> any open driver except i965), always fail. The tests report
>>>> GLXBadFBConfig and just die. I think the piglit_init function isn't
>>>> even reached.
>>>>
>>>> I don't use EGL.
>>>>
>>>> Marek
>>>
>>> Marek,
>>>
>>> I tried some experiments with i965 and older versions of Mesa in an
>>> attempt to reproduce your problem, but I can't. In the two experiments
>>> I tried below, the behavior was exactly as expected.
>>>
>>> * Test 1: Against i965 from mesa-7.11, which supports only GL 2.1 and no
>>> GLX_ARB_create_context.
>>>
>>>> PIGLIT_DEBUG=1 PIGLIT_PLATFORM=glx ./gl-3.1-minmax
>>> piglit: debug: waffle_config_choose failed due to WAFFLE_ERROR_UNSUPPORTED_ON_PLATFORM: GLX_ARB_create_context is required in order to request a GL version not equal to the default value 1.0
>>> piglit: info: Failed to create GL 3.1 core context
>>> Mesa: Initializing x86-64 optimizations
>>> Test requires GL version 3.1
>>> PIGLIT: {'result': 'skip' }
>>>
>>>
>>> * Test 2: Against i965 from mesa-9.0.1, which supports GL 3.1 core, and an Xserver
>>> without GLX_ARB_create_context.
>>>
>>>> PIGLIT_DEBUG=1 PIGLIT_PLATFORM=glx ./gl-3.1-minmax
>>> piglit: debug: waffle_config_choose failed due to WAFFLE_ERROR_UNSUPPORTED_ON_PLATFORM: GLX_ARB_create_context is required in order to request a GL version not equal to the default value 1.0
>>> piglit: info: Failed to create GL 3.1 core context
>>> Test requires GL version 3.1
>>> PIGLIT: {'result': 'skip' }
>>>
>>>
>>> Please run, with PIGLIT_DEBUG=1, the piglit test that's causing you trouble
>>> and send me the output. Hopefully that will be enough for me to identify
>>> and fix the bug.
>>
>> PIGLIT_DEBUG doesn't print anything. All I get is:
>>
>> X Error of failed request:  GLXBadFBConfig
>>   Major opcode of failed request:  154 (GLX)
>>   Minor opcode of failed request:  34 ()
>>   Serial number of failed request:  22
>>   Current serial number in output stream:  20
>>
>> I get the same error with gallium and classic swrast.
>>
>> Marek
>
> Even with swrast, I'm not getting GLXBadFBConfig.
>
>> PIGLIT_DEBUG=1 PIGLIT_PLATFORM=glx LIBGL_ALWAYS_SOFTWARE=1 bin/gl-3.1-minmax
> piglit: debug: waffle_config_choose failed due to WAFFLE_ERROR_UNSUPPORTED_ON_PLATFORM: GLX_ARB_create_context is required in order to request a GL version not equal to the default value 1.0
> piglit: info: Failed to create GL 3.1 core context
> Test requires GL version 3.1
> PIGLIT: {'result': 'skip' }
>
>
> The GLX call that likely emits GLXBadFBConfig is the call to glXCreateNewContext
> at glx_context.c:144 (lines relative to waffle-1.2.2). That call succeeds for me,
> so I don't know why it's failing for you. The following information would help:
>
> 1. Break at glx_context.c:144.
> 2. Verify that the call to glXCreateNewContext there emits GLXBadFBConfig.
> 3. Give me the backtrace there.
> 4. In gdb, give me the output of `print *config`.
> 5. Give me the output of glxinfo.

After some investigation, it's actually glXCreateContextAttribsARB
that fails, which is what I would expect to fail if it can't create a
core context. The implementation is in mesa/src/glx/create_context.c.
I'm cc'in Ian, because he implemented it.

glXCreateContextAttribsARB falls back to indirect rendering if it
fails to create a direct context and then
xcb_glx_create_context_attribs_arb_checked returns GLXBadFBConfig.

I have 2 options there:
- don't try indirect rendering and return NULL
- don't call __glXSendErrorForXcb (which kills the app) and return NULL

Both options yield the behavior waffle expects. My guess is that we
should remove the call to __glXSendErrorForXcb, but I'm not sure if
it's a correct fix.

BTW I have X Server 1.13.

Marek