[Intel-gfx] [PATCH 07/12] drm/i915: Write the SDVO reg twice on IBX

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

On IBX the SDVO/HDMI register write may be masked when enabling the
port, so it may need to written twice. The HDMI code does this, but
the SDVO code does not. Add the workaround to the SDVO code as well.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_sdvo.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 0a06257..e3e9c98 100644
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -243,6 +243,14 @@ static void intel_sdvo_write_sdvox(struct intel_sdvo *intel_sdvo, u32 val)
 	if (intel_sdvo->sdvo_reg == PCH_SDVOB) {
 		I915_WRITE(intel_sdvo->sdvo_reg, val);
 		POSTING_READ(intel_sdvo->sdvo_reg);
+		/*
+		 * HW workaround, need to write this twice for issue
+		 * that may result in first write getting masked.
+		 */
+		if (HAS_PCH_IBX(dev)) {
+			I915_WRITE(intel_sdvo->sdvo_reg, val);
+			POSTING_READ(intel_sdvo->sdvo_reg);
+		}
 		return;
 	}
 
-- 
2.0.5