Hi G.G, > -----Original Message----- > From: Mun, Gwan-gyeong <gwan-gyeong.mun@xxxxxxxxx> > Sent: Tuesday, August 23, 2022 11:14 PM > To: Roper, Matthew D <matthew.d.roper@xxxxxxxxx>; Sripada, Radhakrishna > <radhakrishna.sripada@xxxxxxxxx> > Cc: intel-gfx@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH] drm/i915: Skip Bit12 fw domain reset for gen12+ > > > > On 8/18/22 3:00 PM, Matt Roper wrote: > > On Wed, Aug 17, 2022 at 03:43:04PM -0700, Radhakrishna Sripada wrote: > >> Bit12 of the Forcewake request register should not be cleared post > >> gen12. Do not touch this bit while clearing during fw domain reset. > >> > >> Bspec: 52542 > >> > >> Signed-off-by: Sushma Venkatesh Reddy > <sushma.venkatesh.reddy@xxxxxxxxx> > >> Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx> > >> --- > >> drivers/gpu/drm/i915/intel_uncore.c | 5 ++++- > >> 1 file changed, 4 insertions(+), 1 deletion(-) > >> > >> diff --git a/drivers/gpu/drm/i915/intel_uncore.c > b/drivers/gpu/drm/i915/intel_uncore.c > >> index a852c471d1b3..c85e2b686c95 100644 > >> --- a/drivers/gpu/drm/i915/intel_uncore.c > >> +++ b/drivers/gpu/drm/i915/intel_uncore.c > >> @@ -113,7 +113,10 @@ fw_domain_reset(const struct > intel_uncore_forcewake_domain *d) > >> * off in ICL+), so no waiting for acks > >> */ > >> /* WaRsClearFWBitsAtReset:bdw,skl */ > > > > While we're at it, let's remove the "bdw,skl" from this comment since > > it's misleading and doesn't match the code. We do still apply this > > workaround on other pre-gen12 platforms than just those two. > > > > Aside from the comment tweak, > > > > Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx> > > > >> - fw_clear(d, 0xffff); > >> + if (GRAPHICS_VER(d->uncore->i915) >= 12) > Hi Radhakrishna Sripada, > > In bspec 52542, there is an explanation that BIT12 should not be set for > address 0xA188 corresponding to FORCEWAKE_MT/FORCEWAKE_GT_GEN9, but > in > bspec 52466, there is no explanation that BIT12 should not be set for > address 0xA278, address of FORCEWAKE_RENDER_GEN9. > > I ask if fw_domain_reset() should perform fw_clear() by comparing not > only GRAPHICS_VER() >= 12 but also checking of FW_DOMAIN_ID_RENDER and > FW_DOMAIN_ID_GT values. Based on the note in 52542, all other WA notes are overridden by the comment. So unless stated otherwise, it should apply to this register as well. Created a bspec issue to request for additional clarification just to be safe. Will send an additional patch if the comment contradicts our understanding. Thanks, RK > > Br, > G.G. > >> + fw_clear(d, 0xefff); > >> + else > >> + fw_clear(d, 0xffff); > >> } > >> > >> static inline void > >> -- > >> 2.25.1 > >> > >
