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

[Chad Versace]

On 11/29/2012 01:35 PM, Eric Anholt wrote:
> Chad Versace <chad.versace at linux.intel.com> writes:
> 
>> On 11/28/2012 12:22 PM, Marek Olšák wrote:
>>> 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
>>
>> I third option is to add a new waffle function that allows clients
>> to register various error handlers.
>>
>> When writing waffle, I completely
>> forgot that the default handler for X errors simply exits. I was working
>> from Wayland's model, where unhandled errors are ignored. Another lesson
>> learned for waffle 2.0.
> 
> If waffle is generating the requests, it should suppress the errors on
> its own.

I think that's sensible. Marek has submitted a patch that does so for
glXCreateContext*, which is now on master and the stable branch.