[PATCH 096/222] drm/i915: drop buggy write to FDI_RX_CHICKEN register
From: Herton Ronaldo Krzesinski
Date: Wed Jan 16 2013 - 11:03:21 EST
3.5.7.3 -stable review patch. If anyone has any objections, please let me know.
------------------
From: Daniel Vetter <daniel.vetter@xxxxxxxx>
commit 607a6f7a6621f65706ff536b2615ee65b5c2f575 upstream.
Jani Nikula noticed that the parentheses are wrong and we & the bit
with the register address instead of the read-back value. He sent a
patch to correct that.
On second look, we write the same register in the previous line, and
the w/a seems to be to set FDI_RX_PHASE_SYNC_POINTER_OVR to enable the
logic, then keep always set FDI_RX_PHASE_SYNC_POINTER_OVR and toggle
FDI_RX_PHASE_SYNC_POINTER_EN before/after enabling the pc transcoder.
So the right things seems to be to simply kill the 2nd write.
Cc: Jani Nikula <jani.nikula@xxxxxxxxx>
Reviewed-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
[danvet: Dropped a bogus ~ from the commit message that somehow crept
in.]
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
[ herton: this looks a good bug fix, which also makes the next patch,
"drm/i915: disable cpt phase pointer fdi rx workaround", easier to apply ]
Signed-off-by: Herton Ronaldo Krzesinski <herton.krzesinski@xxxxxxxxxxxxx>
---
drivers/gpu/drm/i915/intel_display.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c69444a..98ea04e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -2609,9 +2609,6 @@ static void ironlake_fdi_disable(struct drm_crtc *crtc)
/* Ironlake workaround, disable clock pointer after downing FDI */
if (HAS_PCH_IBX(dev)) {
I915_WRITE(FDI_RX_CHICKEN(pipe), FDI_RX_PHASE_SYNC_POINTER_OVR);
- I915_WRITE(FDI_RX_CHICKEN(pipe),
- I915_READ(FDI_RX_CHICKEN(pipe) &
- ~FDI_RX_PHASE_SYNC_POINTER_EN));
} else if (HAS_PCH_CPT(dev)) {
cpt_phase_pointer_disable(dev, pipe);
}
--
1.7.9.5
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