[Intel-xe] [PATCH] drm/xe/pvc: Don't try to invalidate AuxCCS TLB

[Matt Roper]

On Thu, May 25, 2023 at 06:46:03PM +0530, Kalvala, Haridhar wrote:
> 
> On 5/25/2023 12:56 AM, Matt Roper wrote:
> > Generally !has_flatccs implies that a platform has AuxCCS compression
> > and thus needs to invalidate the AuxCCS TLB.  However PVC is a special
> > case because it has no compression of either type (FlatCCS or AuxCCS)
> > so we should avoid writing to non-existent AuxCCS registers.
> 
> Hi Matt,
> 
> Looks good to me.
> 
> Just a query, if their is no compression support, do we need to remove flag
> 
> ".has_flat_ccs" from PVC description structure.

You mean from graphics_xehpc?  That already indicates that flat_ccs is
disabled:

        .has_flat_ccs = 0,

which is correct.  The change here is just to make sure that the driver
doesn't assume that lack of flatccs implies that we have auxccs instead
(on PVC we have neither flatccs nor auxccs).


Matt

> 
> Regards,
> 
> Haridhar Kalvala
> 
> > Signed-off-by: Matt Roper <matthew.d.roper at intel.com>
> > ---
> >   drivers/gpu/drm/xe/xe_ring_ops.c | 16 ++++++++++++++--
> >   1 file changed, 14 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_ring_ops.c b/drivers/gpu/drm/xe/xe_ring_ops.c
> > index 74c1b5dfbaee..d2fa0b4c8bcc 100644
> > --- a/drivers/gpu/drm/xe/xe_ring_ops.c
> > +++ b/drivers/gpu/drm/xe/xe_ring_ops.c
> > @@ -190,6 +190,18 @@ static void __emit_job_gen12_copy(struct xe_sched_job *job, struct xe_lrc *lrc,
> >   	xe_lrc_write_ring(lrc, dw, i * sizeof(*dw));
> >   }
> > +static bool has_aux_ccs(struct xe_device *xe)
> > +{
> > +	/*
> > +	 * PVC is a special case that has no compression of either type
> > +	 * (FlatCCS or AuxCCS).
> > +	 */
> > +	if (xe->info.platform == XE_PVC)
> > +		return false;
> > +
> > +	return !xe->info.has_flat_ccs;
> > +}
> > +
> >   static void __emit_job_gen12_video(struct xe_sched_job *job, struct xe_lrc *lrc,
> >   				   u64 batch_addr, u32 seqno)
> >   {
> > @@ -202,7 +214,7 @@ static void __emit_job_gen12_video(struct xe_sched_job *job, struct xe_lrc *lrc,
> >   	dw[i++] = preparser_disable(true);
> >   	/* hsdes: 1809175790 */
> > -	if (!xe->info.has_flat_ccs) {
> > +	if (has_aux_ccs(xe)) {
> >   		if (decode)
> >   			i = emit_aux_table_inv(gt, VD0_AUX_NV, dw, i);
> >   		else
> > @@ -248,7 +260,7 @@ static void __emit_job_gen12_render_compute(struct xe_sched_job *job,
> >   	i = emit_pipe_invalidate(mask_flags, dw, i);
> >   	/* hsdes: 1809175790 */
> > -	if (!xe->info.has_flat_ccs)
> > +	if (has_aux_ccs(xe))
> >   		i = emit_aux_table_inv(gt, GFX_CCS_AUX_NV, dw, i);
> >   	dw[i++] = preparser_disable(false);
> 
> -- 
> Regards,
> Haridhar Kalvala
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation