[Mesa-dev] [PATCH v2 103/103] i965/gen7: expose OpenGL 4.0 on Haswell

[Kenneth Graunke]

On Tuesday, October 18, 2016 5:12:27 PM PDT Ian Romanick wrote:
> On 10/11/2016 02:02 AM, Iago Toral Quiroga wrote:
> > ARB_gpu_shader_fp64 was the last piece missing. Notice that some
> > hardware and kernel combinations do not support pipelined register
> > writes, which are required for some OpenGL 4.0 features, in which
> > case the driver won't expose 4.0.
> > ---
> >  src/mesa/drivers/dri/i965/intel_extensions.c | 2 ++
> >  src/mesa/drivers/dri/i965/intel_screen.c     | 2 +-
> >  2 files changed, 3 insertions(+), 1 deletion(-)
> > 
> > diff --git a/src/mesa/drivers/dri/i965/intel_extensions.c b/src/mesa/drivers/dri/i965/intel_extensions.c
> > index 0491145..a291cd5 100644
> > --- a/src/mesa/drivers/dri/i965/intel_extensions.c
> > +++ b/src/mesa/drivers/dri/i965/intel_extensions.c
> > @@ -272,6 +272,8 @@ intelInitExtensions(struct gl_context *ctx)
> >  
> >     if (brw->gen >= 8)
> >        ctx->Const.GLSLVersion = 440;
> > +   else if (brw->is_haswell)
> > +      ctx->Const.GLSLVersion = 400;
> >     else if (brw->gen >= 6)
> >        ctx->Const.GLSLVersion = 330;
> >     else
> > diff --git a/src/mesa/drivers/dri/i965/intel_screen.c b/src/mesa/drivers/dri/i965/intel_screen.c
> > index 9b23bac..1af7fe6 100644
> > --- a/src/mesa/drivers/dri/i965/intel_screen.c
> > +++ b/src/mesa/drivers/dri/i965/intel_screen.c
> > @@ -1445,7 +1445,7 @@ set_max_gl_versions(struct intel_screen *screen)
> >        dri_screen->max_gl_es2_version = has_astc ? 32 : 31;
> >        break;
> >     case 7:
> > -      dri_screen->max_gl_core_version = 33;
> > +      dri_screen->max_gl_core_version = screen->devinfo.is_haswell ? 40 : 33;
> 
> I *think* this needs to take the pipelined register writes into
> consideration.  My understanding is if you say 40 here, then
> glXCreateContextAttribs will allow creation of an OpenGL 4.0 context...
> but the context may only be 3.3.

Good catch, Ian.  Checking brw->can_do_pipelined_register_writes here
would be right...but it's awkward, since it's stored in the context, and
doesn't get populated until we actually make a context and run things on
the GPU.  That's probably not too feasible here in screen init time,
where we're trying to decide what kind of contexts to even support.

To make life easier, I might just do:

   dri_screen->max_gl_core_version = screen->has_mi_math_and_lrr ? 40 : 33;

which is the check we use for ARB_query_buffer_object.  On Haswell,
it implies a high enough command parser version that we can do
everything we need.  (We could actually get away with an older kernel
version, but I'm not sure I care...as we move toward 4.1/4.2/4.3 we'd
need to bump it higher anyway...)

The one gotcha is that has_mi_math_and_lrr / cmd_parser_version get
initialized after set_max_gl_versions() is called, so you'll need to
reorder those in the caller.  Should be straightforward.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 801 bytes
Desc: This is a digitally signed message part.
URL: <https://lists.freedesktop.org/archives/mesa-dev/attachments/20161018/aac3ea34/attachment.sig>