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

[Upadhyay, Tejas]

> -----Original Message-----
> From: De Marchi, Lucas <lucas.demarchi at intel.com>
> Sent: Friday, February 7, 2025 5:03 AM
> To: Atwood, Matthew S <matthew.s.atwood at intel.com>
> Cc: Roper, Matthew D <matthew.d.roper at intel.com>; intel-
> xe at lists.freedesktop.org; Upadhyay, Tejas <tejas.upadhyay at intel.com>
> Subject: Re: [PATCH] drm/xe/xe3: Extend wa_15015404425 for xe3
> 
> On Thu, Feb 06, 2025 at 09:12:49AM -0800, Matt Atwood wrote:
> >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 at 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?
> 
> at the very least, use XE_WA(). You may need to extend the matches it knows
> about to implement what you need here.

As far as I remember, init of wa_oob was little late so we could not use XE_WA. I am not sure if init wa_oob moved elsewhere and we are good here!

I was seeing below assert and thus we decided to go with what we have here,

It asserts,
[  778.229096] xe 0000:00:02.0: [drm] [drm] Assertion `(gt)->wa_active.oob_initialized` failed!
               platform: LUNARLAKE subplatform: 1
               graphics: (null) 0.00 step **
               media: (null) 0.00 step **
               tile: 0 VRAM 0 B
               GT: 0 type 0
[  778.229121] WARNING: CPU: 1 PID: 1567 at drivers/gpu/drm/xe/xe_mmio.c:133 mmio_flush_pending_writes+0x33d/0x350 [xe]

Tejas
> 
> Lucas De Marchi
> 
> >+Lucas
> >>
> >>
> >> Matt
> >>
> >> >
> >> > v2: query based off SOC stepping
> >> >
> >> > Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> >> > Signed-off-by: Matt Atwood <matthew.s.atwood at 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