drm/i915: Write the SDVO reg twice on IBX

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@linux.intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 0a0625761f4265905810e27d4f61526a5914528d..e3e9c98eaf526c4e5ae5ea058e9401b2403c2344 100644 (file)
--- 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;
        }