[Mesa-dev] [PATCH] i965/cs: Initialize GPGPU Thread Count

[Jordan Justen]

On 2015-06-25 11:34:59, Ben Widawsky wrote:
> On Thu, Jun 11, 2015 at 09:04:45PM -0700, Jordan Justen wrote:
> > +   desc[dw++] = 0;
> > +   const uint32_t media_threads =
> > +      brw->gen >= 8 ?
> > +      SET_FIELD(threads, GEN8_MEDIA_GPGPU_THREAD_COUNT) :
> > +      SET_FIELD(threads, MEDIA_GPGPU_THREAD_COUNT);
> > +   desc[dw++] = media_threads;
> 
> What's the deal with, "The maximum value for global barriers is limited by the
> number of threads in the system, or by 511," Can we add an assert?

I guess we are using a local barrier, so "the maximum value is the
number of threads in a subslice for local barriers".

How about I add assert(threads <= brw->max_cs_threads)? Although, in
brw_compute:brw_emit_gpgpu_walker we have a similar assertion.

-Jordan

> >  
> >     BEGIN_BATCH(4);
> >     OUT_BATCH(MEDIA_INTERFACE_DESCRIPTOR_LOAD << 16 | (4 - 2));
> > diff --git a/src/mesa/drivers/dri/i965/brw_defines.h b/src/mesa/drivers/dri/i965/brw_defines.h
> > index f6da305..2a8f500 100644
> > --- a/src/mesa/drivers/dri/i965/brw_defines.h
> > +++ b/src/mesa/drivers/dri/i965/brw_defines.h
> > @@ -2495,6 +2495,11 @@ enum brw_wm_barycentric_interp_mode {
> >  # define MEDIA_VFE_STATE_CURBE_ALLOC_MASK       INTEL_MASK(15, 0)
> >  
> >  #define MEDIA_INTERFACE_DESCRIPTOR_LOAD         0x7002
> > +/* GEN7 DW5, GEN8+ DW6 */
> > +# define MEDIA_GPGPU_THREAD_COUNT_SHIFT         0
> > +# define MEDIA_GPGPU_THREAD_COUNT_MASK          INTEL_MASK(7, 0)
> > +# define GEN8_MEDIA_GPGPU_THREAD_COUNT_SHIFT    0
> > +# define GEN8_MEDIA_GPGPU_THREAD_COUNT_MASK     INTEL_MASK(9, 0)
> >  #define MEDIA_STATE_FLUSH                       0x7004
> >  #define GPGPU_WALKER                            0x7105
> >  /* GEN8+ DW2 */
> > -- 
> > 2.1.4
> > 
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