On Mon, Jan 07, 2019 at 11:19:31AM -0800, Matt Roper wrote: > On Mon, Jan 07, 2019 at 01:23:50PM +0100, Michał Winiarski wrote: > > On Mon, Jan 07, 2019 at 01:01:16PM +0200, Joonas Lahtinen wrote: > > > Quoting José Roberto de Souza (2019-01-04 19:37:00) > > > > According to Workaround database ICL also needs > > > > WaEnablePreemptionGranularityControlByUMD, to allow userspace to do > > > > fine-granularity preemptions per-context. > > > > > > I must wonder where is the userspace component that needs this, and why > > > it hasn't been noticed earlier? > > > > > > Or is this one more of the cases when no userspace actually uses the > > > register? > > > > It's used: > > https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/mesa/drivers/dri/i965/brw_state_upload.c#L64 > > > > -Michał > > Wasn't this just an artificial i915-only workaround that was added to > prevent breakage of pre-preemption UMD's? Initial gen9 driver releases > didn't support preemption, so when preemption support did get added to > i915, the kernel had to force object-level off by default at context > creation to avoid breaking old userspace that didn't build batch buffers > with all the necessary preemption workarounds. This CS_CHICKEN1 > register was then exposed to userspace so that newer, preemption-aware > userspace could opt back in if it properly supported preemption. It wasn't just old userspace vs preeemption-aware userspace. Even the preemption-aware userspace needs to downgrade its preemption granularity as a WA, see: https://gitlab.freedesktop.org/mesa/mesa/blob/master/src/mesa/drivers/dri/i965/brw_draw.c#L876 > For gen11, there shouldn't be any "old" userspace around that doesn't > support preemption, so shouldn't the kernel just leave object-level > preemption enabled by default (meaning there's no need to expose this > register to userspace to allow it to explicitly opt-in)? Agreed, as a bonus we don't allow anyone to explicity opt-out - which is great, as long as everything works reliably. -Michał > > Matt > > > > > > Regards, Joonas > > > > > > > > > > > BSpec: 11348 > > > > Cc: Oscar Mateo <oscar.mateo@xxxxxxxxx> > > > > Cc: Radhakrishna Sripada <radhakrishna.sripada@xxxxxxxxx> > > > > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx> > > > > --- > > > > drivers/gpu/drm/i915/intel_workarounds.c | 9 ++++++--- > > > > 1 file changed, 6 insertions(+), 3 deletions(-) > > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_workarounds.c b/drivers/gpu/drm/i915/intel_workarounds.c > > > > index 480c53a2ecb5..bbc5a66faa07 100644 > > > > --- a/drivers/gpu/drm/i915/intel_workarounds.c > > > > +++ b/drivers/gpu/drm/i915/intel_workarounds.c > > > > @@ -1014,7 +1014,7 @@ static void gen9_whitelist_build(struct i915_wa_list *w) > > > > /* WaVFEStateAfterPipeControlwithMediaStateClear:skl,bxt,glk,cfl */ > > > > whitelist_reg(w, GEN9_CTX_PREEMPT_REG); > > > > > > > > - /* WaEnablePreemptionGranularityControlByUMD:skl,bxt,kbl,cfl,[cnl] */ > > > > + /* WaEnablePreemptionGranularityControlByUMD:skl,bxt,kbl,cfl,[cnl,icl] */ > > > > whitelist_reg(w, GEN8_CS_CHICKEN1); > > > > > > > > /* WaAllowUMDToModifyHDCChicken1:skl,bxt,kbl,glk,cfl */ > > > > @@ -1068,6 +1068,9 @@ static void icl_whitelist_build(struct i915_wa_list *w) > > > > > > > > /* WaAllowUMDToModifySamplerMode:icl */ > > > > whitelist_reg(w, GEN10_SAMPLER_MODE); > > > > + > > > > + /* WaEnablePreemptionGranularityControlByUMD:icl */ > > > > + whitelist_reg(w, GEN8_CS_CHICKEN1); > > > > } > > > > > > > > void intel_engine_init_whitelist(struct intel_engine_cs *engine) > > > > @@ -1186,8 +1189,8 @@ static void rcs_engine_wa_init(struct intel_engine_cs *engine) > > > > GEN7_DISABLE_SAMPLER_PREFETCH); > > > > } > > > > > > > > - if (IS_GEN(i915, 9) || IS_CANNONLAKE(i915)) { > > > > - /* WaEnablePreemptionGranularityControlByUMD:skl,bxt,kbl,cfl,cnl */ > > > > + if (IS_GEN_RANGE(i915, 9, 11)) { > > > > + /* WaEnablePreemptionGranularityControlByUMD:skl,bxt,kbl,cfl,cnl,icl */ > > > > wa_masked_en(wal, > > > > GEN7_FF_SLICE_CS_CHICKEN1, > > > > GEN9_FFSC_PERCTX_PREEMPT_CTRL); > > > > -- > > > > 2.20.1 > > > > > > > > _______________________________________________ > > > > Intel-gfx mailing list > > > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > > _______________________________________________ > > > Intel-gfx mailing list > > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Matt Roper > Graphics Software Engineer > IoTG Platform Enabling & Development > Intel Corporation > (916) 356-2795 _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
