Re: [PATCH] drm/xe/xe3: Extend wa_15015404425 for xe3

[Matt Atwood <matthew.s.atwood@intel.com>]

On Thu, Jan 30, 2025 at 09:30:30AM -0800, Matt Roper wrote:
> On Tue, Jan 28, 2025 at 04:55:51PM -0800, Matt Atwood wrote:
> > From: Tejas Upadhyay <tejas.upadhyay@intel.com>
> > 
> > wa_15015404425 applies to xe3 A0 step as well.
> 
> We really need a better commit message explaining how this workaround is
> different from our usual ones and why it needs to be handled in a
> special way that's different from all of our other workarounds,
> especially since someone who just quickly skims the workaround database
> without digging into the details is going to incorrectly think this just
> applies to Xe2 media and isn't relevant to PTL.
Ack.
> 
> I was kind of hoping we'd add a more well-defined infrastructure for
> handling device / SoC workarounds.  Adding quick hacks like this is
> going to get out of hand quickly if more of these start showing up.
Any particular ideas here?
+Lucas
> 
> 
> Matt
> 
> > 
> > v2: query based off SOC stepping
> > 
> > Signed-off-by: Tejas Upadhyay <tejas.upadhyay@intel.com>
> > Signed-off-by: Matt Atwood <matthew.s.atwood@intel.com>
> > ---
> >  drivers/gpu/drm/xe/xe_mmio.c | 13 +++++++------
> >  drivers/gpu/drm/xe/xe_step.h |  2 ++
> >  2 files changed, 9 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> > index d321a21aacf0..98d068ad33bb 100644
> > --- a/drivers/gpu/drm/xe/xe_mmio.c
> > +++ b/drivers/gpu/drm/xe/xe_mmio.c
> > @@ -150,14 +150,15 @@ int xe_mmio_init(struct xe_device *xe)
> >  static void mmio_flush_pending_writes(struct xe_mmio *mmio)
> >  {
> >  #define DUMMY_REG_OFFSET	0x130030
> > +	struct xe_device *xe = tile_to_xe(mmio->tile);
> >  	int i;
> >  
> > -	if (mmio->tile->xe->info.platform != XE_LUNARLAKE)
> > -		return;
> > -
> > -	/* 4 dummy writes */
> > -	for (i = 0; i < 4; i++)
> > -		writel(0, mmio->regs + DUMMY_REG_OFFSET);
> > +	if (xe->info.platform == XE_LUNARLAKE ||
> > +	    (xe->info.platform == XE_PANTHERLAKE &&
> > +	     xe->info.revid == PTL_SOC_STEP_A0))
> > +		/* 4 dummy writes */
> > +		for (i = 0; i < 4; i++)
> > +			writel(0, mmio->regs + DUMMY_REG_OFFSET);
> >  }
> >  
> >  u8 xe_mmio_read8(struct xe_mmio *mmio, struct xe_reg reg)
> > diff --git a/drivers/gpu/drm/xe/xe_step.h b/drivers/gpu/drm/xe/xe_step.h
> > index 686cb59200c2..879486a818e9 100644
> > --- a/drivers/gpu/drm/xe/xe_step.h
> > +++ b/drivers/gpu/drm/xe/xe_step.h
> > @@ -20,4 +20,6 @@ static inline u32 xe_step_to_gmdid(enum xe_step step) { return step - STEP_A0; }
> >  
> >  const char *xe_step_name(enum xe_step step);
> >  
> > +#define PTL_SOC_STEP_A0  0x0
> > +
> >  #endif
> > -- 
> > 2.45.0
> > 
> 
> -- 
> Matt Roper
> Graphics Software Engineer
> Linux GPU Platform Enablement
> Intel Corporation