[Mesa-dev] [PATCH] svga: use the debug callback to report issues to the state tracker

[Ilia Mirkin]

On Fri, Dec 4, 2015 at 6:14 PM, Jose Fonseca <jfonseca at vmware.com> wrote:
> On 04/12/15 22:40, Jose Fonseca wrote:
>>
>> On 04/12/15 20:04, Ilia Mirkin wrote:
>>>
>>> On Fri, Dec 4, 2015 at 3:01 PM, Brian Paul <brianp at vmware.com> wrote:
>>>>
>>>> On 12/04/2015 12:46 PM, Ilia Mirkin wrote:
>>>>>
>>>>>
>>>>> On Fri, Dec 4, 2015 at 2:42 PM, Brian Paul <brianp at vmware.com> wrote:
>>>>>>
>>>>>>
>>>>>> +   if (templ->poly_smooth && svga->debug.callback.debug_message) {
>>>>>> +      /* note: we always need a % something in the message string */
>>>>>
>>>>>
>>>>>
>>>>> Why? Did I mess something up?
>>>>
>>>>
>>>>
>>>> If I write it without the dummy %s I get:
>>>>
>>>> In file included from
>>>> ../../../../src/gallium/auxiliary/util/u_inlines.h:36:0,
>>>>                   from svga_pipe_rasterizer.c:29:
>>>> svga_pipe_rasterizer.c: In function 'svga_create_rasterizer_state':
>>>> ../../../../src/gallium/auxiliary/util/u_debug.h:273:40: error: expected
>>>> expression before ')' token
>>>>                          fmt, __VA_ARGS__); \
>>>>                                          ^
>>>> svga_pipe_rasterizer.c:357:7: note: in expansion of macro
>>>> 'pipe_debug_message'
>>>>         pipe_debug_message(&svga->debug.callback, CONFORMANCE,
>>>>         ^
>>>>
>>>
>>> Hmmmm... so that'd be a "yes" to me messing it up :) I'll have a look
>>> to see if there's something simple I can do here. Off-hand it feels
>>> like it should be #__VA_ARGS__? Been a while since I looked at the
>>> specifics of all this.
>>>
>>>>
>>>>>
>>>>> BTW, right now this callback is only set for debug contexts. Perhaps
>>>>> that was not an ideal decision... just an FYI though.
>>>>
>>>>
>>>>
>>>> apitrace creates a debug context so that's the main thing for me
>>>> right now.
>>>> But it might be nice if setting MESA_DEBUG would cause the debug/info
>>>> messages to be printed to stderr for those apps that don't use
>>>> GL_ARB_debug_output.
>>>
>>>
>>> Yeah, we should probably also throw in Enable/Disable hooks into
>>> st/mesa that flip it on/off when flipping GL_DEBUG_OUTPUT (or whatever
>>> the enum is).
>>>
>>> BTW, note that apitrace cuts messages off after 100 of them which is
>>> pretty annoying -- I opened an issue at
>>> https://github.com/apitrace/apitrace/issues/395 a while back.
>>
>>
>> Not just "100", but 100 *per ID*.
>>
>> Which is very different.
>>
>> Why is it so annoying?  A patch for an option is welcome anyway BTW.
>>
>
> I noticed that pipe_debug_message() doesn't take a message ID.

It's a little clever... this is why pipe_debug_message is a macro.
Every separate callsite gets its own id. It's initialized to 0, and
passed in as a pointer... the mesa function actually assigns it a new
id if the passed in id is 0. It's a bit racey and definitely a weird
API, but... it was easy :)

  -ilia