drm/i915/sdvo: Propagate i2c error from switching DDC control bus.

[pandora-kernel.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 05f5313..fa9dbb7 100644 (file)
--- a/drivers/gpu/drm/i915/intel_sdvo.c
+++ b/drivers/gpu/drm/i915/intel_sdvo.c
@@ -530,8 +530,8 @@ static int intel_sdvo_get_pixel_multiplier(struct drm_display_mode *mode)
  * 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_sdvo *intel_sdvo,
-                                             u8 target)
+static int intel_sdvo_set_control_bus_switch(struct intel_sdvo *intel_sdvo,
+                                            u8 target)
 {
        u8 out_buf[2], cmd_buf[2], ret_value[2], ret;
        struct i2c_msg msgs[] = {
@@ -557,9 +557,10 @@ static void intel_sdvo_set_control_bus_switch(struct intel_sdvo *intel_sdvo,
        };
 
        intel_sdvo_debug_write(intel_sdvo, SDVO_CMD_SET_CONTROL_BUS_SWITCH,
-                                       &target, 1);
+                              &target, 1);
        /* write the DDC switch command argument */
-       intel_sdvo_write_byte(intel_sdvo, SDVO_I2C_ARG_0, target);
+       if (!intel_sdvo_write_byte(intel_sdvo, SDVO_I2C_ARG_0, target))
+               return -EIO;
 
        out_buf[0] = SDVO_I2C_OPCODE;
        out_buf[1] = SDVO_CMD_SET_CONTROL_BUS_SWITCH;
@@ -569,17 +570,20 @@ static void intel_sdvo_set_control_bus_switch(struct intel_sdvo *intel_sdvo,
        ret_value[1] = 0;
 
        ret = i2c_transfer(intel_sdvo->base.i2c_bus, msgs, 3);
+       if (ret < 0)
+               return ret;
        if (ret != 3) {
                /* failure in I2C transfer */
                DRM_DEBUG_KMS("I2c transfer returned %d\n", ret);
-               return;
+               return -EIO;
        }
        if (ret_value[0] != SDVO_CMD_STATUS_SUCCESS) {
                DRM_DEBUG_KMS("DDC switch command returns response %d\n",
-                                       ret_value[0]);
-               return;
+                             ret_value[0]);
+               return -EIO;
        }
-       return;
+
+       return 0;
 }
 
 static bool intel_sdvo_set_value(struct intel_sdvo *intel_sdvo, u8 cmd, const void *data, int len)
@@ -1982,13 +1986,18 @@ static int intel_sdvo_master_xfer(struct i2c_adapter *i2c_adap,
 {
        struct intel_sdvo *intel_sdvo;
        const struct i2c_algorithm *algo;
+       int ret;
 
        intel_sdvo = container_of(i2c_adap->algo_data,
                                  struct intel_sdvo,
                                  base);
        algo = intel_sdvo->base.i2c_bus->algo;
 
-       intel_sdvo_set_control_bus_switch(intel_sdvo, intel_sdvo->ddc_bus);
+       ret = intel_sdvo_set_control_bus_switch(intel_sdvo,
+                                               intel_sdvo->ddc_bus);
+       if (ret)
+               return ret;
+
        return algo->master_xfer(i2c_adap, msgs, num);
 }