drm/i915: fix VGA detect on IGDNG

Check FORCE_DETECT bit to be clear for the finish
of hotplug detect process. Also check possible mono
monitor which should also be marked as connected.

Signed-off-by: Zhenyu Wang <zhenyuw@linux.intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 8 insertions, 4 deletions

diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index d6a1a6e5539a..4cf8e2e88a40 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -156,6 +156,9 @@ static bool intel_igdng_crt_detect_hotplug(struct drm_connector *connector)
 
         temp = adpa = I915_READ(PCH_ADPA);
 
+        adpa &= ~ADPA_DAC_ENABLE;
+        I915_WRITE(PCH_ADPA, adpa);
+
         adpa &= ~ADPA_CRT_HOTPLUG_MASK;
 
         adpa |= (ADPA_CRT_HOTPLUG_PERIOD_128 |
@@ -169,13 +172,14 @@ static bool intel_igdng_crt_detect_hotplug(struct drm_connector *connector)
         DRM_DEBUG("pch crt adpa 0x%x", adpa);
         I915_WRITE(PCH_ADPA, adpa);
 
-        /* This might not be needed as not specified in spec...*/
-        udelay(1000);
+        while ((I915_READ(PCH_ADPA) & ADPA_CRT_HOTPLUG_FORCE_TRIGGER) != 0)
+                ;
 
         /* Check the status to see if both blue and green are on now */
         adpa = I915_READ(PCH_ADPA);
-        if ((adpa & ADPA_CRT_HOTPLUG_MONITOR_MASK) ==
-                        ADPA_CRT_HOTPLUG_MONITOR_COLOR)
+        adpa &= ADPA_CRT_HOTPLUG_MONITOR_MASK;
+        if ((adpa == ADPA_CRT_HOTPLUG_MONITOR_COLOR) ||
+                (adpa == ADPA_CRT_HOTPLUG_MONITOR_MONO))
                 ret = true;
         else
                 ret = false;