drm/i915: add Ironlake clock gating workaround for FDI link training
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index a72335e..5a22887 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2782,6 +2782,7 @@
#define FDI_RXA_CHICKEN 0xc200c
#define FDI_RXB_CHICKEN 0xc2010
#define FDI_RX_PHASE_SYNC_POINTER_ENABLE (1)
+#define FDI_RX_CHICKEN(pipe) _PIPE(pipe, FDI_RXA_CHICKEN, FDI_RXB_CHICKEN)
/* CPU: FDI_TX */
#define FDI_TXA_CTL 0x60100
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 349710a..5812fc7 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1714,6 +1714,9 @@
POSTING_READ(reg);
udelay(150);
+ /* Ironlake workaround, enable clock pointer after FDI enable*/
+ I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_ENABLE);
+
reg = FDI_RX_IIR(pipe);
for (tries = 0; tries < 5; tries++) {
temp = I915_READ(reg);
@@ -2192,6 +2195,11 @@
POSTING_READ(reg);
udelay(100);
+ /* Ironlake workaround, disable clock pointer after downing FDI */
+ I915_WRITE(FDI_RX_CHICKEN(pipe),
+ I915_READ(FDI_RX_CHICKEN(pipe) &
+ ~FDI_RX_PHASE_SYNC_POINTER_ENABLE));
+
/* still set train pattern 1 */
reg = FDI_TX_CTL(pipe);
temp = I915_READ(reg);