drm/i915: Read the response after issuing DDC bus switch command

[mv-sheeva.git] / drivers / gpu / drm / i915 / intel_sdvo.c

diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
index 24a3dc99716c5c8e5490ded0abd503312a544f2a..f899afd924b4f4f29c00adaf1007e2570b084f44 100644 (file)
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -462,14 +462,63 @@ static int intel_sdvo_get_pixel_multiplier(struct drm_display_mode *mode)
 }
 
 /**
- * Don't check status code from this as it switches the bus back to the
- * SDVO chips which defeats the purpose of doing a bus switch in the first
- * place.
+ * Try to read the response after issuie the DDC switch command. But it
+ * is noted that we must do the action of reading response and issuing DDC
+ * switch command in one I2C transaction. Otherwise when we try to start
+ * another I2C transaction after issuing the DDC bus switch, it will be
+ * switched to the internal SDVO register.
  */
 static void intel_sdvo_set_control_bus_switch(struct intel_output *intel_output,
                                              u8 target)
 {
-       intel_sdvo_write_cmd(intel_output, SDVO_CMD_SET_CONTROL_BUS_SWITCH, &target, 1);
+       struct intel_sdvo_priv *sdvo_priv = intel_output->dev_priv;
+       u8 out_buf[2], cmd_buf[2], ret_value[2], ret;
+       struct i2c_msg msgs[] = {
+               {
+                       .addr = sdvo_priv->slave_addr >> 1,
+                       .flags = 0,
+                       .len = 2,
+                       .buf = out_buf,
+               },
+               /* the following two are to read the response */
+               {
+                       .addr = sdvo_priv->slave_addr >> 1,
+                       .flags = 0,
+                       .len = 1,
+                       .buf = cmd_buf,
+               },
+               {
+                       .addr = sdvo_priv->slave_addr >> 1,
+                       .flags = I2C_M_RD,
+                       .len = 1,
+                       .buf = ret_value,
+               },
+       };
+
+       intel_sdvo_debug_write(intel_output, SDVO_CMD_SET_CONTROL_BUS_SWITCH,
+                                       &target, 1);
+       /* write the DDC switch command argument */
+       intel_sdvo_write_byte(intel_output, SDVO_I2C_ARG_0, target);
+
+       out_buf[0] = SDVO_I2C_OPCODE;
+       out_buf[1] = SDVO_CMD_SET_CONTROL_BUS_SWITCH;
+       cmd_buf[0] = SDVO_I2C_CMD_STATUS;
+       cmd_buf[1] = 0;
+       ret_value[0] = 0;
+       ret_value[1] = 0;
+
+       ret = i2c_transfer(intel_output->i2c_bus, msgs, 3);
+       if (ret != 3) {
+               /* failure in I2C transfer */
+               DRM_DEBUG_KMS("I2c transfer returned %d\n", ret);
+               return;
+       }
+       if (ret_value[0] != SDVO_CMD_STATUS_SUCCESS) {
+               DRM_DEBUG_KMS("DDC switch command returns response %d\n",
+                                       ret_value[0]);
+               return;
+       }
+       return;
 }
 
 static bool intel_sdvo_set_target_input(struct intel_output *intel_output, bool target_0, bool target_1)
@@ -2662,6 +2711,7 @@ static void intel_sdvo_create_enhance_property(struct drm_connector *connector)
 
 bool intel_sdvo_init(struct drm_device *dev, int output_device)
 {
+       struct drm_i915_private *dev_priv = dev->dev_private;
        struct drm_connector *connector;
        struct intel_output *intel_output;
        struct intel_sdvo_priv *sdvo_priv;
@@ -2708,10 +2758,12 @@ bool intel_sdvo_init(struct drm_device *dev, int output_device)
                intel_output->ddc_bus = intel_i2c_create(dev, GPIOE, "SDVOB DDC BUS");
                sdvo_priv->analog_ddc_bus = intel_i2c_create(dev, GPIOA,
                                                "SDVOB/VGA DDC BUS");
+               dev_priv->hotplug_supported_mask |= SDVOB_HOTPLUG_INT_STATUS;
        } else {
                intel_output->ddc_bus = intel_i2c_create(dev, GPIOE, "SDVOC DDC BUS");
                sdvo_priv->analog_ddc_bus = intel_i2c_create(dev, GPIOA,
                                                "SDVOC/VGA DDC BUS");
+               dev_priv->hotplug_supported_mask |= SDVOC_HOTPLUG_INT_STATUS;
        }
 
        if (intel_output->ddc_bus == NULL)