drm/i915: Remove "i2c_speed" nonsense from child device table

I have no evidence for this byte being used this way, and lots of
counterexamples.  Restore the struct to its empirical definition and
patch up gmbus setup to match.

Signed-off-by: Adam Jackson <ajax@redhat.com>
Acked-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Keith Packard <keithp@keithp.com>

drivers/gpu/drm/i915/i915_drv.h

@@ -139,7 +139,6 @@ struct sdvo_device_mapping {
 	u8 slave_addr;
 	u8 dvo_wiring;
 	u8 i2c_pin;
-	u8 i2c_speed;
 	u8 ddc_pin;
 };
 

drivers/gpu/drm/i915/intel_bios.c

@@ -403,15 +403,13 @@ parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
 			p_mapping->dvo_wiring = p_child->dvo_wiring;
 			p_mapping->ddc_pin = p_child->ddc_pin;
 			p_mapping->i2c_pin = p_child->i2c_pin;
-			p_mapping->i2c_speed = p_child->i2c_speed;
 			p_mapping->initialized = 1;
-			DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d, i2c_speed=%d\n",
+			DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d\n",
 				      p_mapping->dvo_port,
 				      p_mapping->slave_addr,
 				      p_mapping->dvo_wiring,
 				      p_mapping->ddc_pin,
-				      p_mapping->i2c_pin,
-				      p_mapping->i2c_speed);
+				      p_mapping->i2c_pin);
 		} else {
 			DRM_DEBUG_KMS("Maybe one SDVO port is shared by "
 					 "two SDVO device.\n");

drivers/gpu/drm/i915/intel_bios.h

@@ -202,8 +202,7 @@ struct bdb_general_features {
 struct child_device_config {
 	u16 handle;
 	u16 device_type;
-	u8  i2c_speed;
-	u8  rsvd[9];
+	u8  device_id[10]; /* ascii string */
 	u16 addin_offset;
 	u8  dvo_port; /* See Device_PORT_* above */
 	u8  i2c_pin;

drivers/gpu/drm/i915/intel_sdvo.c

@@ -1896,7 +1896,7 @@ intel_sdvo_select_i2c_bus(struct drm_i915_private *dev_priv,
 			  struct intel_sdvo *sdvo, u32 reg)
 {
 	struct sdvo_device_mapping *mapping;
-	u8 pin, speed;
+	u8 pin;
 
 	if (IS_SDVOB(reg))
 		mapping = &dev_priv->sdvo_mappings[0];
@@ -1904,18 +1904,16 @@ intel_sdvo_select_i2c_bus(struct drm_i915_private *dev_priv,
 		mapping = &dev_priv->sdvo_mappings[1];
 
 	pin = GMBUS_PORT_DPB;
-	speed = GMBUS_RATE_1MHZ >> 8;
-	if (mapping->initialized) {
+	if (mapping->initialized)
 		pin = mapping->i2c_pin;
-		speed = mapping->i2c_speed;
-	}
 
 	if (pin < GMBUS_NUM_PORTS) {
 		sdvo->i2c = &dev_priv->gmbus[pin].adapter;
-		intel_gmbus_set_speed(sdvo->i2c, speed);
+		intel_gmbus_set_speed(sdvo->i2c, GMBUS_RATE_1MHZ >> 8);
 		intel_gmbus_force_bit(sdvo->i2c, true);
-	} else
+	} else {
 		sdvo->i2c = &dev_priv->gmbus[GMBUS_PORT_DPB].adapter;
+	}
 }
 
 static bool