[PATCH] drm/xe/xe2_lpg: Add workaround 14021567978

[Upadhyay, Tejas]

> -----Original Message-----
> From: Roper, Matthew D <matthew.d.roper at intel.com>
> Sent: Thursday, April 4, 2024 9:03 PM
> To: Upadhyay, Tejas <tejas.upadhyay at intel.com>
> Cc: intel-xe at lists.freedesktop.org; De Marchi, Lucas
> <lucas.demarchi at intel.com>
> Subject: Re: [PATCH] drm/xe/xe2_lpg: Add workaround 14021567978
> 
> On Thu, Apr 04, 2024 at 03:05:29PM +0530, Tejas Upadhyay wrote:
> > Workaround 14021567978 applies to RenderCS xe2_lpg
> 
> This is one of those rare workarounds that's documented as not only applying
> to the single platform that has the record in the WA database, but also
> carrying forward to all future platforms forever (at least until they make a
> permanent documentation change).  Since this starts with the Xe2 family in
> general (not specific to LNL or BMG) and goes forever, it might be best to write
> the bounds as

But this 14021567978  is only talking about xe2_lpg. Even if it applies to future platforms, we will have new WA #s for them which then we can mark with "#WA1, #WA2" and modify version range. Should not we go buy WA#s to keep track?

Thanks,
Tejas
> 
>         GRAPHICS_VERSION_RANGE(2000, XE_RTP_END_VERSION_UNDEFINED);
> 
> Also, it's still technically considered a "workaround" due to being documented
> in the workaround database with a lineage number, rather than a tuning
> setting documented on bspec 72161, so we should probably keep this in
> xe_wa.c instead of xe_tuning.c.
> 
> 
> Matt
> 
> >
> > Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_tuning.c | 7 +++++++
> >  1 file changed, 7 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/xe/xe_tuning.c
> > b/drivers/gpu/drm/xe/xe_tuning.c index bb6db2817ada..cc65e5b4353b
> > 100644
> > --- a/drivers/gpu/drm/xe/xe_tuning.c
> > +++ b/drivers/gpu/drm/xe/xe_tuning.c
> > @@ -93,6 +93,13 @@ static const struct xe_rtp_entry_sr lrc_tunings[] = {
> >
> REG_FIELD_PREP(L3_PWM_TIMER_INIT_VAL_MASK, 0x7f)))
> >  	},
> >
> > +	/* Xe2_LPG */
> > +
> > +	{ XE_RTP_NAME("Tuning: TBIMR fast clip"),
> > +	  XE_RTP_RULES(GRAPHICS_VERSION(2004),
> ENGINE_CLASS(RENDER)),
> > +	  XE_RTP_ACTIONS(SET(CHICKEN_RASTER_2, TBIMR_FAST_CLIP))
> > +	},
> > +
> >  	{}
> >  };
> >
> > --
> > 2.25.1
> >
> 
> --
> Matt Roper
> Graphics Software Engineer
> Linux GPU Platform Enablement
> Intel Corporation