[PATCH V2 2/2] drm/xe/xe2lpm: Add permanent wa_14020756599

[Upadhyay, Tejas]

> -----Original Message-----
> From: Roper, Matthew D <matthew.d.roper at intel.com>
> Sent: Wednesday, May 15, 2024 9:01 AM
> To: Upadhyay, Tejas <tejas.upadhyay at intel.com>
> Cc: intel-xe at lists.freedesktop.org; Ghimiray, Himal Prasad
> <himal.prasad.ghimiray at intel.com>
> Subject: Re: [PATCH V2 2/2] drm/xe/xe2lpm: Add permanent
> wa_14020756599
> 
> On Tue, Apr 30, 2024 at 01:26:09PM +0530, Tejas Upadhyay wrote:
> > For xe2_lpm Wa_14020756599 is applied to all steppings.
> >
> > V2:
> >   - Remove engine filter video decode
> >   - Fix typo GRAPHICS/MEDIA/s - Himal
> >
> > Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_wa.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_wa.c b/drivers/gpu/drm/xe/xe_wa.c
> > index 7657aadf217c..76f7a7e3ee61 100644
> > --- a/drivers/gpu/drm/xe/xe_wa.c
> > +++ b/drivers/gpu/drm/xe/xe_wa.c
> > @@ -701,6 +701,12 @@ static const struct xe_rtp_entry_sr lrc_was[] = {
> >  			     DIS_AUTOSTRIP))
> >  	},
> >
> > +	/* Xe2_LPM */
> > +	{ XE_RTP_NAME("14020756599"),
> > +	  XE_RTP_RULES(MEDIA_VERSION(2000)),
> 
> Even though this workaround needs to be applied on any platform with
> media version 20.00 (regardless of the primary GT's version), there's still only
> a single copy of this register and it resides within the primary GT as part of
> the render engine's LRC (bspec 65182).  This is a pretty unusual case (turning
> off something in a different hardware unit than what the workaround is
> marked against) and we might need to do something special for this
> workaround since we need to emit this workaround specifically as part of the
> RCS engine's LRC (you don't have an engine filter here, so it's going to try to
> put it in every engine's LRC), and the use of MEDIA_VERSION also implicitly
> makes our RTP framework use the media GT to apply it rather than the
> primary GT.
> Since this register is within the GSI range, applying the workaround through
> the media GT will make it try to write to offset
> (0x380000+0x5588) which won't do what we want.
> 
> For now the only platforms that have media 20.00 also have primary GT
> versions that match the Xe2_LPG version number, so we could probably get
> away with just putting a comment in the table saying that we're not adding
> the Xe2_LPM entry for now since the Xe2_LPG entry already covers the
> necessary programming.  But if they ever pair media 20.00 with some other
> primary GT version that doesn't need this workaround, we may have to think
> about adding more flags to RTP to deal with this kind of situation.

Do you think, handling it this way would be good for future use well?

diff --git a/drivers/gpu/drm/xe/xe_rtp.c b/drivers/gpu/drm/xe/xe_rtp.c
index fb44cc7521d8..54b99f31a538 100644
--- a/drivers/gpu/drm/xe/xe_rtp.c
+++ b/drivers/gpu/drm/xe/xe_rtp.c
@@ -309,6 +309,14 @@ bool xe_rtp_match_first_render_or_compute(const struct xe_gt *gt,
                hwe->engine_id == __ffs(render_compute_mask);
 }

+bool xe_rtp_match_media_need_wa(const struct xe_gt *gt,
+                               const struct xe_hw_engine *hwe)
+{
+       if (!xe_gt_is_media_type(gt) && hwe->class == XE_ENGINE_CLASS_RENDER)
+               return MEDIA_VER(gt_to_xe(gt)) == 20;
+       return false;
+}
+
 bool xe_rtp_match_first_gslice_fused_off(const struct xe_gt *gt,
                                         const struct xe_hw_engine *hwe)
 {
diff --git a/drivers/gpu/drm/xe/xe_wa.c b/drivers/gpu/drm/xe/xe_wa.c
index 05db53c1448c..8a374afb789f 100644
--- a/drivers/gpu/drm/xe/xe_wa.c
+++ b/drivers/gpu/drm/xe/xe_wa.c
@@ -227,6 +227,11 @@ static const struct xe_rtp_entry_sr gt_was[] = {
          XE_RTP_ACTIONS(SET(VDBOX_CGCTL3F08(0), CG3DDISHRS_CLKGATE_DIS)),
          XE_RTP_ENTRY_FLAG(FOREACH_ENGINE),
        },
+       { XE_RTP_NAME("14020756599"),
+         XE_RTP_RULES(FUNC(xe_rtp_match_media_need_wa)),
+         XE_RTP_ACTIONS(SET(WM_CHICKEN3, HIZ_PLANE_COMPRESSION_DIS))
+       },
+

        /* Xe2_HPM */

Thanks,
Tejas
> 
> 
> Matt
> 
> > +	  XE_RTP_ACTIONS(SET(WM_CHICKEN3,
> HIZ_PLANE_COMPRESSION_DIS))
> > +	},
> > +
> >  	{}
> >  };
> >
> > --
> > 2.25.1
> >
> 
> --
> Matt Roper
> Graphics Software Engineer
> Linux GPU Platform Enablement
> Intel Corporation