[PATCH] drm/i915/psr: Implement PSR2 w/a for gen9

Daniel Vetter
2016-05-19T07:14:25Z

Found this while browsing Bspec. Looks like it applies to both skl and
kbl.

v2: Also for bxt (Art).

Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Sonika Jindal <sonika.jindal@intel.com>
Cc: Durgadoss R <durgadoss.r@intel.com>
Cc: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@intel.com>
Cc: "Runyan, Arthur J" <arthur.j.runyan@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
drivers/gpu/drm/i915/i915_reg.h | 1 +
drivers/gpu/drm/i915/intel_pm.c | 17 +++++++++++++++--
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 0f99e67f2114..c51368744e9e 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -6043,6 +6043,7 @@ enum skl_disp_power_wells {
#define CHICKEN_PAR1_1 _MMIO(0x42080)
#define DPA_MASK_VBLANK_SRD (1 << 15)
#define FORCE_ARB_IDLE_PLANES (1 << 14)
+#define SKL_EDP_PSR_FIX_RDWRAP (1 << 3)

#define _CHICKEN_PIPESL_1_A 0x420b0
#define _CHICKEN_PIPESL_1_B 0x420b4
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index e0d5405a8b15..8d42261daf1f 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -58,6 +58,10 @@ static void bxt_init_clock_gating(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;

+ /* See Bspec note for PSR2_CTL bit 31, Wa#828:bxt */
+ I915_WRITE(CHICKEN_PAR1_1,
+ I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
+
/* WaDisableSDEUnitClockGating:bxt */
I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
GEN8_SDEUNIT_CLOCK_GATE_DISABLE);
@@ -6845,6 +6849,15 @@ static void gen8_set_l3sqc_credits(struct drm_i915_private *dev_priv,
I915_WRITE(GEN7_MISCCPCTL, misccpctl);
}

+static void skylake_init_clock_gating(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+
+ /* See Bspec note for PSR2_CTL bit 31, Wa#828:skl,kbl */
+ I915_WRITE(CHICKEN_PAR1_1,
+ I915_READ(CHICKEN_PAR1_1) | SKL_EDP_PSR_FIX_RDWRAP);
+}
+
static void broadwell_init_clock_gating(struct drm_device *dev)
{
struct drm_i915_private *dev_priv = dev->dev_private;
@@ -7307,9 +7320,9 @@ static void nop_init_clock_gating(struct drm_device *dev)
void intel_init_clock_gating_hooks(struct drm_i915_private *dev_priv)
{
if (IS_SKYLAKE(dev_priv))
- dev_priv->display.init_clock_gating = nop_init_clock_gating;
+ dev_priv->display.init_clock_gating = skylake_init_clock_gating;
else if (IS_KABYLAKE(dev_priv))
- dev_priv->display.init_clock_gating = nop_init_clock_gating;
+ dev_priv->display.init_clock_gating = skylake_init_clock_gating;
else if (IS_BROXTON(dev_priv))
dev_priv->display.init_clock_gating = bxt_init_clock_gating;
else if (IS_BROADWELL(dev_priv))
--
2.8.1