On Wed, Feb 8, 2017 at 6:33 PM, Ville Syrjälä <ville.syrj...@linux.intel.com> wrote: > On Wed, Feb 08, 2017 at 06:10:31PM +0000, Robert Bragg wrote: >> This workaround for BDW was incomplete as it also requires EUTC clock >> gating to be disabled via UCGCTL1. > > IIRC that matches what I told Ben years ago when the w/a was first > being added, and matches what I put in the CHV code when it still > had this w/a. Presumably it still holds for BDW.
Poking into this I see now that 3e470eaaee5 which removes the corresponding, pre-production, w/a for CHV removed a write to UCGCTL1 which is missing for BDW. > >> >> Signed-off-by: Robert Bragg <rob...@sixbynine.org> >> --- >> drivers/gpu/drm/i915/intel_ringbuffer.c | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c >> b/drivers/gpu/drm/i915/intel_ringbuffer.c >> index 49fa8006c6a2..fa1b400a79d0 100644 >> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c >> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c >> @@ -776,6 +776,7 @@ static int bdw_init_workarounds(struct intel_engine_cs >> *engine) >> /* WaDisableDopClockGating:bdw */ >> WA_SET_BIT_MASKED(GEN7_ROW_CHICKEN2, >> DOP_CLOCK_GATING_DISABLE); >> + WA_SET_BIT(GEN6_UCGCTL1, GEN6_EU_TCUNIT_CLOCK_GATE_DISABLE); > > The UCGCTL registers aren't clobbered by GPU resets and whatnot, so > we've historically kept them in the init_clock_gating() side. Okey, I'll move here. > > Also it's not a masked register, and I'm not sure not all the bits > default to 0, so you shouldn't perhaps just clobber them. Sadly the > spec seems to have gone mad and no longer shows the default values > for registers so I can't double check right now. Ah, oops, I had a read modify write in i915-perf previously but yeah this is no good. Moving this to broadwell_init_clock_gating() as a read modify write is hopefully ok. Thanks for the notes. - Robert > >> >> WA_SET_BIT_MASKED(HALF_SLICE_CHICKEN3, >> GEN8_SAMPLER_POWER_BYPASS_DIS); >> -- >> 2.11.0 >> >> _______________________________________________ >> Intel-gfx mailing list >> Intel-gfx@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
