drm/radeon/kms: add support for hardcoded edids in rom (v2)

Some servers hardcode an edid in rom so that they will
work properly with KVMs.  This is a port of the relevant
code from the ddx.

[airlied: reworked to validate edid at boot stage - and
remove special quirk, if there is a valid EDID in the BIOS rom
we'll just try and use it.]
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/drm_edid.c

@@ -60,8 +60,7 @@
 #define EDID_QUIRK_FIRST_DETAILED_PREFERRED	(1 << 5)
 /* use +hsync +vsync for detailed mode */
 #define EDID_QUIRK_DETAILED_SYNC_PP		(1 << 6)
-/* define the number of Extension EDID block */
-#define MAX_EDID_EXT_NUM 4
+
 
 #define LEVEL_DMT	0
 #define LEVEL_GTF	1
@@ -114,14 +113,14 @@ static const u8 edid_header[] = {
 };
 
 /**
- * edid_is_valid - sanity check EDID data
+ * drm_edid_is_valid - sanity check EDID data
  * @edid: EDID data
  *
  * Sanity check the EDID block by looking at the header, the version number
  * and the checksum.  Return 0 if the EDID doesn't check out, or 1 if it's
  * valid.
  */
-static bool edid_is_valid(struct edid *edid)
+bool drm_edid_is_valid(struct edid *edid)
 {
 	int i, score = 0;
 	u8 csum = 0;
@@ -163,6 +162,7 @@ static bool edid_is_valid(struct edid *edid)
 	}
 	return 0;
 }
+EXPORT_SYMBOL(drm_edid_is_valid);
 
 /**
  * edid_vendor - match a string against EDID's obfuscated vendor field
@@ -1069,8 +1069,8 @@ static int add_detailed_info_eedid(struct drm_connector *connector,
 	}
 
 	/* Chose real EDID extension number */
-	edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
-		       MAX_EDID_EXT_NUM : edid->extensions;
+	edid_ext_num = edid->extensions > DRM_MAX_EDID_EXT_NUM ?
+		DRM_MAX_EDID_EXT_NUM : edid->extensions;
 
 	/* Find CEA extension */
 	for (i = 0; i < edid_ext_num; i++) {
@@ -1152,7 +1152,7 @@ static int drm_ddc_read_edid(struct drm_connector *connector,
 	for (i = 0; i < 4; i++) {
 		if (drm_do_probe_ddc_edid(adapter, buf, len))
 			return -1;
-		if (edid_is_valid((struct edid *)buf))
+		if (drm_edid_is_valid((struct edid *)buf))
 			return 0;
 	}
 
@@ -1177,7 +1177,7 @@ struct edid *drm_get_edid(struct drm_connector *connector,
 	int ret;
 	struct edid *edid;
 
-	edid = kmalloc(EDID_LENGTH * (MAX_EDID_EXT_NUM + 1),
+	edid = kmalloc(EDID_LENGTH * (DRM_MAX_EDID_EXT_NUM + 1),
 		       GFP_KERNEL);
 	if (edid == NULL) {
 		dev_warn(&connector->dev->pdev->dev,
@@ -1195,14 +1195,14 @@ struct edid *drm_get_edid(struct drm_connector *connector,
 	if (edid->extensions != 0) {
 		int edid_ext_num = edid->extensions;
 
-		if (edid_ext_num > MAX_EDID_EXT_NUM) {
+		if (edid_ext_num > DRM_MAX_EDID_EXT_NUM) {
 			dev_warn(&connector->dev->pdev->dev,
 				 "The number of extension(%d) is "
 				 "over max (%d), actually read number (%d)\n",
-				 edid_ext_num, MAX_EDID_EXT_NUM,
-				 MAX_EDID_EXT_NUM);
+				 edid_ext_num, DRM_MAX_EDID_EXT_NUM,
+				 DRM_MAX_EDID_EXT_NUM);
 			/* Reset EDID extension number to be read */
-			edid_ext_num = MAX_EDID_EXT_NUM;
+			edid_ext_num = DRM_MAX_EDID_EXT_NUM;
 		}
 		/* Read EDID including extensions too */
 		ret = drm_ddc_read_edid(connector, adapter, (char *)edid,
@@ -1245,8 +1245,8 @@ bool drm_detect_hdmi_monitor(struct edid *edid)
 		goto end;
 
 	/* Chose real EDID extension number */
-	edid_ext_num = edid->extensions > MAX_EDID_EXT_NUM ?
-		       MAX_EDID_EXT_NUM : edid->extensions;
+	edid_ext_num = edid->extensions > DRM_MAX_EDID_EXT_NUM ?
+		       DRM_MAX_EDID_EXT_NUM : edid->extensions;
 
 	/* Find CEA extension */
 	for (i = 0; i < edid_ext_num; i++) {
@@ -1303,7 +1303,7 @@ int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
 	if (edid == NULL) {
 		return 0;
 	}
-	if (!edid_is_valid(edid)) {
+	if (!drm_edid_is_valid(edid)) {
 		dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
 			 drm_get_connector_name(connector));
 		return 0;

drivers/gpu/drm/radeon/radeon_combios.c

@@ -443,6 +443,39 @@ static uint16_t combios_get_table_offset(struct drm_device *dev,
 
 }
 
+bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev)
+{
+	int edid_info;
+	struct edid *edid;
+	edid_info = combios_get_table_offset(rdev->ddev, COMBIOS_HARDCODED_EDID_TABLE);
+	if (!edid_info)
+		return false;
+
+	edid = kmalloc(EDID_LENGTH * (DRM_MAX_EDID_EXT_NUM + 1),
+		       GFP_KERNEL);
+	if (edid == NULL)
+		return false;
+
+	memcpy((unsigned char *)edid,
+	       (unsigned char *)(rdev->bios + edid_info), EDID_LENGTH);
+
+	if (!drm_edid_is_valid(edid)) {
+		kfree(edid);
+		return false;
+	}
+
+	rdev->mode_info.bios_hardcoded_edid = edid;
+	return true;
+}
+
+struct edid *
+radeon_combios_get_hardcoded_edid(struct radeon_device *rdev)
+{
+	if (rdev->mode_info.bios_hardcoded_edid)
+		return rdev->mode_info.bios_hardcoded_edid;
+	return NULL;
+}
+
 static struct radeon_i2c_bus_rec combios_setup_i2c_bus(struct radeon_device *rdev,
 						       int ddc_line)
 {

drivers/gpu/drm/radeon/radeon_display.c

@@ -352,6 +352,8 @@ static bool radeon_setup_enc_conn(struct drm_device *dev)
 
 int radeon_ddc_get_modes(struct radeon_connector *radeon_connector)
 {
+	struct drm_device *dev = radeon_connector->base.dev;
+	struct radeon_device *rdev = dev->dev_private;
 	int ret = 0;
 
 	if ((radeon_connector->base.connector_type == DRM_MODE_CONNECTOR_DisplayPort) ||
@@ -366,7 +368,9 @@ int radeon_ddc_get_modes(struct radeon_connector *radeon_connector)
 	if (!radeon_connector->edid) {
 		radeon_connector->edid = drm_get_edid(&radeon_connector->base, &radeon_connector->ddc_bus->adapter);
 	}
-
+	/* some servers provide a hardcoded edid in rom for KVMs */
+	if (!radeon_connector->edid)
+		radeon_connector->edid = radeon_combios_get_hardcoded_edid(rdev);
 	if (radeon_connector->edid) {
 		drm_mode_connector_update_edid_property(&radeon_connector->base, radeon_connector->edid);
 		ret = drm_add_edid_modes(&radeon_connector->base, radeon_connector->edid);
@@ -829,6 +833,12 @@ int radeon_modeset_init(struct radeon_device *rdev)
 		return ret;
 	}
 
+	/* check combios for a valid hardcoded EDID - Sun servers */
+	if (!rdev->is_atom_bios) {
+		/* check for hardcoded EDID in BIOS */
+		radeon_combios_check_hardcoded_edid(rdev);
+	}
+
 	if (rdev->flags & RADEON_SINGLE_CRTC)
 		num_crtc = 1;
 
@@ -850,6 +860,8 @@ int radeon_modeset_init(struct radeon_device *rdev)
 
 void radeon_modeset_fini(struct radeon_device *rdev)
 {
+	kfree(rdev->mode_info.bios_hardcoded_edid);
+
 	if (rdev->mode_info.mode_config_initialized) {
 		radeon_hpd_fini(rdev);
 		drm_mode_config_cleanup(rdev->ddev);

drivers/gpu/drm/radeon/radeon_mode.h

@@ -207,7 +207,8 @@ struct radeon_mode_info {
 	struct drm_property *tv_std_property;
 	/* legacy TMDS PLL detect */
 	struct drm_property *tmds_pll_property;
-
+	/* hardcoded DFP edid from BIOS */
+	struct edid *bios_hardcoded_edid;
 };
 
 #define MAX_H_CODE_TIMING_LEN 32
@@ -479,6 +480,9 @@ extern int radeon_crtc_cursor_set(struct drm_crtc *crtc,
 extern int radeon_crtc_cursor_move(struct drm_crtc *crtc,
 				   int x, int y);
 
+extern bool radeon_combios_check_hardcoded_edid(struct radeon_device *rdev);
+extern struct edid *
+radeon_combios_get_hardcoded_edid(struct radeon_device *rdev);
 extern bool radeon_atom_get_clock_info(struct drm_device *dev);
 extern bool radeon_combios_get_clock_info(struct drm_device *dev);
 extern struct radeon_encoder_atom_dig *

include/drm/drm_crtc.h

@@ -801,4 +801,6 @@ extern struct drm_display_mode *drm_gtf_mode(struct drm_device *dev,
 				bool interlaced, int margins);
 extern int drm_add_modes_noedid(struct drm_connector *connector,
 				int hdisplay, int vdisplay);
+
+extern bool drm_edid_is_valid(struct edid *edid);
 #endif /* __DRM_CRTC_H__ */

include/drm/drm_edid.h

@@ -201,4 +201,7 @@ struct edid {
 
 #define EDID_PRODUCT_ID(e) ((e)->prod_code[0] | ((e)->prod_code[1] << 8))
 
+/* define the number of Extension EDID block */
+#define DRM_MAX_EDID_EXT_NUM 4
+
 #endif /* __DRM_EDID_H__ */