2 files changed, 48 insertions, 13 deletions

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 6d567772679b..05b1894fa13d 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -633,6 +633,22 @@
 #define   TV_HOTPLUG_INT_EN                     (1 << 18)
 #define   CRT_HOTPLUG_INT_EN                    (1 << 9)
 #define   CRT_HOTPLUG_FORCE_DETECT              (1 << 3)
+#define CRT_HOTPLUG_ACTIVATION_PERIOD_32        (0 << 8)
+/* must use period 64 on GM45 according to docs */
+#define CRT_HOTPLUG_ACTIVATION_PERIOD_64        (1 << 8)
+#define CRT_HOTPLUG_DAC_ON_TIME_2M              (0 << 7)
+#define CRT_HOTPLUG_DAC_ON_TIME_4M              (1 << 7)
+#define CRT_HOTPLUG_VOLTAGE_COMPARE_40          (0 << 5)
+#define CRT_HOTPLUG_VOLTAGE_COMPARE_50          (1 << 5)
+#define CRT_HOTPLUG_VOLTAGE_COMPARE_60          (2 << 5)
+#define CRT_HOTPLUG_VOLTAGE_COMPARE_70          (3 << 5)
+#define CRT_HOTPLUG_VOLTAGE_COMPARE_MASK        (3 << 5)
+#define CRT_HOTPLUG_DETECT_DELAY_1G             (0 << 4)
+#define CRT_HOTPLUG_DETECT_DELAY_2G             (1 << 4)
+#define CRT_HOTPLUG_DETECT_VOLTAGE_325MV        (0 << 2)
+#define CRT_HOTPLUG_DETECT_VOLTAGE_475MV        (1 << 2)
+#define CRT_HOTPLUG_MASK                        (0x3fc) /* Bits 9-2 */
+
 
 #define PORT_HOTPLUG_STAT       0x61114
 #define   HDMIB_HOTPLUG_INT_STATUS              (1 << 29)
diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
index e58defa247d5..2b6d44381c31 100644
--- a/drivers/gpu/drm/i915/intel_crt.c
+++ b/drivers/gpu/drm/i915/intel_crt.c
@@ -146,20 +146,39 @@ static bool intel_crt_detect_hotplug(struct drm_connector *connector)
 {
         struct drm_device *dev = connector->dev;
         struct drm_i915_private *dev_priv = dev->dev_private;
-        u32 temp;
-
-        unsigned long timeout = jiffies + msecs_to_jiffies(1000);
-
-        temp = I915_READ(PORT_HOTPLUG_EN);
-
-        I915_WRITE(PORT_HOTPLUG_EN,
-                   temp | CRT_HOTPLUG_FORCE_DETECT | (1 << 5));
+        u32 hotplug_en;
+        int i, tries = 0;
+        /*
+         * On 4 series desktop, CRT detect sequence need to be done twice
+         * to get a reliable result.
+         */
 
-        do {
-                if (!(I915_READ(PORT_HOTPLUG_EN) & CRT_HOTPLUG_FORCE_DETECT))
-                        break;
-                msleep(1);
-        } while (time_after(timeout, jiffies));
+        if (IS_G4X(dev) && !IS_GM45(dev))
+                tries = 2;
+        else
+                tries = 1;
+        hotplug_en = I915_READ(PORT_HOTPLUG_EN);
+        hotplug_en &= ~(CRT_HOTPLUG_MASK);
+        hotplug_en |= CRT_HOTPLUG_FORCE_DETECT;
+
+        if (IS_GM45(dev))
+                hotplug_en |= CRT_HOTPLUG_ACTIVATION_PERIOD_64;
+
+        hotplug_en |= CRT_HOTPLUG_VOLTAGE_COMPARE_50;
+
+        for (i = 0; i < tries ; i++) {
+                unsigned long timeout;
+                /* turn on the FORCE_DETECT */
+                I915_WRITE(PORT_HOTPLUG_EN, hotplug_en);
+                timeout = jiffies + msecs_to_jiffies(1000);
+                /* wait for FORCE_DETECT to go off */
+                do {
+                        if (!(I915_READ(PORT_HOTPLUG_EN) &
+                                        CRT_HOTPLUG_FORCE_DETECT))
+                                break;
+                        msleep(1);
+                } while (time_after(timeout, jiffies));
+        }
 
         if ((I915_READ(PORT_HOTPLUG_STAT) & CRT_HOTPLUG_MONITOR_MASK) ==
             CRT_HOTPLUG_MONITOR_COLOR)