From: Eugeni Dodonov <eugeni.dodonov at intel.com> This is yet another workaround related to clock gating which we need on Ivy Bridge. Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=41353 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=44610 Tested-by: Eugeni Dodonov <eugeni.dodonov at intel.com> Signed-off-by: Eugeni Dodonov <eugeni.dodonov at intel.com> Signed-off-by: Kenneth Graunke <kenneth at whitecape.org> --- drivers/gpu/drm/i915/i915_reg.h | 1 + drivers/gpu/drm/i915/intel_display.c | 5 +++++ 2 files changed, 6 insertions(+), 0 deletions(-) diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index c3afb78..80fd6b5 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -3618,6 +3618,7 @@ #define GT_FIFO_NUM_RESERVED_ENTRIES 20 #define GEN6_UCGCTL2 0x9404 +# define GEN6_RCZUNIT_CLOCK_GATE_DISABLE (1 << 13) # define GEN6_RCPBUNIT_CLOCK_GATE_DISABLE (1 << 12) # define GEN6_RCCUNIT_CLOCK_GATE_DISABLE (1 << 11) diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index f1744aa..070c946 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -8461,6 +8461,11 @@ static void ivybridge_init_clock_gating(struct drm_device *dev) I915_WRITE(WM2_LP_ILK, 0); I915_WRITE(WM1_LP_ILK, 0); + /* According to the spec, bit 13 (RCZUNIT) must be set on IVB. + * This implements the WaDisableRCZUnitClockGating workaround. + */ + I915_WRITE(GEN6_UCGCTL2, GEN6_RCZUNIT_CLOCK_GATE_DISABLE); + I915_WRITE(ILK_DSPCLK_GATE, IVB_VRHUNIT_CLK_GATE); I915_WRITE(IVB_CHICKEN3, -- 1.7.7.1
