drm/radeon/kms: fix hardcoded EDID handling

On some servers there is a hardcoded EDID provided
in the vbios so that the driver will always see a
display connected even if something like a KVM
prevents traditional means like DDC or load
detection from working properly.  Also most
server boards with DVI are not actually DVI, but
DVO connected to a virtual KVM service processor.
If we fail to detect a monitor via DDC or load
detection and a hardcoded EDID is available, use
it.

Additionally, when using the hardcoded EDID, use
a copy of it rather than the actual one stored
in the driver as the detect() and get_modes()
functions may free it if DDC is successful.

This fixes the virtual KVM on several internal
servers.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/radeon_combios.c

@@ -448,7 +448,7 @@ static uint16_t combios_get_table_offset(struct drm_device *dev,
 
 bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev)
 {
-	int edid_info;
+	int edid_info, size;
 	struct edid *edid;
 	unsigned char *raw;
 	edid_info = combios_get_table_offset(rdev->ddev, COMBIOS_HARDCODED_EDID_TABLE);
@@ -456,11 +456,12 @@ bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev)
 		return false;
 
 	raw = rdev->bios + edid_info;
-	edid = kmalloc(EDID_LENGTH * (raw[0x7e] + 1), GFP_KERNEL);
+	size = EDID_LENGTH * (raw[0x7e] + 1);
+	edid = kmalloc(size, GFP_KERNEL);
 	if (edid == NULL)
 		return false;
 
-	memcpy((unsigned char *)edid, raw, EDID_LENGTH * (raw[0x7e] + 1));
+	memcpy((unsigned char *)edid, raw, size);
 
 	if (!drm_edid_is_valid(edid)) {
 		kfree(edid);
@@ -468,6 +469,7 @@ bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev)
 	}
 
 	rdev->mode_info.bios_hardcoded_edid = edid;
+	rdev->mode_info.bios_hardcoded_edid_size = size;
 	return true;
 }
 
@@ -475,8 +477,17 @@ bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev)
 struct edid *
 radeon_bios_get_hardcoded_edid(struct radeon_device *rdev)
 {
-	if (rdev->mode_info.bios_hardcoded_edid)
-		return rdev->mode_info.bios_hardcoded_edid;
+	struct edid *edid;
+
+	if (rdev->mode_info.bios_hardcoded_edid) {
+		edid = kmalloc(rdev->mode_info.bios_hardcoded_edid_size, GFP_KERNEL);
+		if (edid) {
+			memcpy((unsigned char *)edid,
+			       (unsigned char *)rdev->mode_info.bios_hardcoded_edid,
+			       rdev->mode_info.bios_hardcoded_edid_size);
+			return edid;
+		}
+	}
 	return NULL;
 }
 

drivers/gpu/drm/radeon/radeon_connectors.c

@@ -629,6 +629,8 @@ static int radeon_vga_mode_valid(struct drm_connector *connector,
 static enum drm_connector_status
 radeon_vga_detect(struct drm_connector *connector, bool force)
 {
+	struct drm_device *dev = connector->dev;
+	struct radeon_device *rdev = dev->dev_private;
 	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
 	struct drm_encoder *encoder;
 	struct drm_encoder_helper_funcs *encoder_funcs;
@@ -679,6 +681,17 @@ radeon_vga_detect(struct drm_connector *connector, bool force)
 
 	if (ret == connector_status_connected)
 		ret = radeon_connector_analog_encoder_conflict_solve(connector, encoder, ret, true);
+
+	/* RN50 and some RV100 asics in servers often have a hardcoded EDID in the
+	 * vbios to deal with KVMs. If we have one and are not able to detect a monitor
+	 * by other means, assume the CRT is connected and use that EDID.
+	 */
+	if ((!rdev->is_atom_bios) &&
+	    (ret == connector_status_disconnected) &&
+	    rdev->mode_info.bios_hardcoded_edid_size) {
+		ret = connector_status_connected;
+	}
+
 	radeon_connector_update_scratch_regs(connector, ret);
 	return ret;
 }
@@ -790,6 +803,8 @@ static int radeon_dvi_get_modes(struct drm_connector *connector)
 static enum drm_connector_status
 radeon_dvi_detect(struct drm_connector *connector, bool force)
 {
+	struct drm_device *dev = connector->dev;
+	struct radeon_device *rdev = dev->dev_private;
 	struct radeon_connector *radeon_connector = to_radeon_connector(connector);
 	struct drm_encoder *encoder = NULL;
 	struct drm_encoder_helper_funcs *encoder_funcs;
@@ -829,8 +844,6 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
 			 * you don't really know what's connected to which port as both are digital.
 			 */
 			if (radeon_connector->shared_ddc && (ret == connector_status_connected)) {
-				struct drm_device *dev = connector->dev;
-				struct radeon_device *rdev = dev->dev_private;
 				struct drm_connector *list_connector;
 				struct radeon_connector *list_radeon_connector;
 				list_for_each_entry(list_connector, &dev->mode_config.connector_list, head) {
@@ -895,6 +908,19 @@ radeon_dvi_detect(struct drm_connector *connector, bool force)
 		ret = radeon_connector_analog_encoder_conflict_solve(connector, encoder, ret, true);
 	}
 
+	/* RN50 and some RV100 asics in servers often have a hardcoded EDID in the
+	 * vbios to deal with KVMs. If we have one and are not able to detect a monitor
+	 * by other means, assume the DFP is connected and use that EDID.  In most
+	 * cases the DVI port is actually a virtual KVM port connected to the service
+	 * processor.
+	 */
+	if ((!rdev->is_atom_bios) &&
+	    (ret == connector_status_disconnected) &&
+	    rdev->mode_info.bios_hardcoded_edid_size) {
+		radeon_connector->use_digital = true;
+		ret = connector_status_connected;
+	}
+
 out:
 	/* updated in get modes as well since we need to know if it's analog or digital */
 	radeon_connector_update_scratch_regs(connector, ret);

drivers/gpu/drm/radeon/radeon_mode.h

@@ -239,6 +239,7 @@ struct radeon_mode_info {
 	struct drm_property *underscan_vborder_property;
 	/* hardcoded DFP edid from BIOS */
 	struct edid *bios_hardcoded_edid;
+	int bios_hardcoded_edid_size;
 
 	/* pointer to fbdev info structure */
 	struct radeon_fbdev *rfbdev;