drm/i915: Disable SR when more than one pipe is enabled
Self Refresh should be disabled on dual plane configs. Otherwise, as
the SR watermark is not calculated for such configs, switching to non
VGA mode causes FIFO underrun and display flicker.
This fixes Korg Bug #14897.
Signed-off-by: David John <davidjon@xenontk.org>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: stable@kernel.org
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 5f14dfb..12775df 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2520,6 +2520,10 @@
sr_entries = roundup(sr_entries / cacheline_size, 1);
DRM_DEBUG("self-refresh entries: %d\n", sr_entries);
I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
+ } else {
+ /* Turn off self refresh if both pipes are enabled */
+ I915_WRITE(FW_BLC_SELF, I915_READ(FW_BLC_SELF)
+ & ~FW_BLC_SELF_EN);
}
DRM_DEBUG("Setting FIFO watermarks - A: %d, B: %d, SR %d\n",
@@ -2563,6 +2567,10 @@
srwm = 1;
srwm &= 0x3f;
I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN);
+ } else {
+ /* Turn off self refresh if both pipes are enabled */
+ I915_WRITE(FW_BLC_SELF, I915_READ(FW_BLC_SELF)
+ & ~FW_BLC_SELF_EN);
}
DRM_DEBUG_KMS("Setting FIFO watermarks - A: 8, B: 8, C: 8, SR %d\n",
@@ -2631,6 +2639,10 @@
if (srwm < 0)
srwm = 1;
I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN | (srwm & 0x3f));
+ } else {
+ /* Turn off self refresh if both pipes are enabled */
+ I915_WRITE(FW_BLC_SELF, I915_READ(FW_BLC_SELF)
+ & ~FW_BLC_SELF_EN);
}
DRM_DEBUG_KMS("Setting FIFO watermarks - A: %d, B: %d, C: %d, SR %d\n",