misc fixes for VC4

[Rob Clark]

On Sat, Jan 3, 2015 at 12:35 PM, Keith Packard <keithp at keithp.com> wrote:
> Rob Clark <robdclark at gmail.com> writes:
>
>> hmm, what minimum gl and gles version do we need to expose instanced
>> drawing?   Or any other useful extensions that glamor could use?  Not
>> sure if that would make a difference between gl vs gles?
>
> We use instanced drawing on anything with GLSL version 1.30 or later.
>
> As for extensions, we check for:
>
> GL_EXT_texture_format_BGRA8888
> GL_KHR_debug
> GL_MESA_pack_invert
> GL_EXT_framebuffer_blit
> GL_ARB_map_buffer_range
> GL_ARB_buffer_storage
> GL_NV_texture_barrier
> GL_OES_EGL_image
>
>> At any rate, we still have the problem that glamor will see that the
>> driver supports both gles and gl, and would have to somehow choose
>> which paths to use.. although I guess we could just pick based on
>> vendor name for freedreno/vc4/etc..
>
> I think we'd rather use real GL on devices that have a real GL driver;
> however, we need to avoid fallbacks in the driver, which means creating
> some way for the driver to tell glamor what paths to avoid...

I guess to start with, we could use hard-coded table keyed by vendor
name, perhaps.. although that is a bit lame

maybe inventing a glIsEmulatedMESA(GLenum) type thing would be a good idea?

>> (But one of these days I'll actually get around to building latest
>> xserver and start playing and benchmarking w/ glamor... and once I
>> actually start getting into the code I may actually have something
>> intelligent to suggest :-P)
>
> That would be helpful.

consider it a new-year's resolution :-P

BR,
-R

> --
> -keith