dtrm/edid: Allow comma separated edid binaries. (v3)

Allow comma separated filenames in the edid_firmware parameter.

For example:

edid_firmware=eDP-1:edid/1280x480.bin,DP-2:edid/1920x1080.bin

v2: Use strsep() to simplify parsing of comma seperated string. (Matt)
    Move initial bail before strdup. (Matt)
v3: Changed conditionals after while loop to make more readable (Jani)
    Updated kernel-parameters.txt to reflect changes (Jani)

Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Matt Roper <matthew.d.roper@intel.com>
Signed-off-by: Bob Paauwe <bob.j.paauwe@intel.com>
[danvet: Flatten else control flow and appease checkpatch.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 33 insertions, 8 deletions

diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
index c5605fe4907e..1f445e9bd768 100644
--- a/drivers/gpu/drm/drm_edid_load.c
+++ b/drivers/gpu/drm/drm_edid_load.c
@@ -264,20 +264,43 @@ out:
 int drm_load_edid_firmware(struct drm_connector *connector)
 {
 	const char *connector_name = connector->name;
-	char *edidname = edid_firmware, *last, *colon;
+	char *edidname, *last, *colon, *fwstr, *edidstr, *fallback = NULL;
 	int ret;
 	struct edid *edid;
 
-	if (*edidname == '\0')
+	if (edid_firmware[0] == '\0')
 		return 0;
 
-	colon = strchr(edidname, ':');
-	if (colon != NULL) {
-		if (strncmp(connector_name, edidname, colon - edidname))
-			return 0;
-		edidname = colon + 1;
-		if (*edidname == '\0')
+	/*
+	 * If there are multiple edid files specified and separated
+	 * by commas, search through the list looking for one that
+	 * matches the connector.
+	 *
+	 * If there's one or more that don't't specify a connector, keep
+	 * the last one found one as a fallback.
+	 */
+	fwstr = kstrdup(edid_firmware, GFP_KERNEL);
+	edidstr = fwstr;
+
+	while ((edidname = strsep(&edidstr, ","))) {
+		colon = strchr(edidname, ':');
+		if (colon != NULL) {
+			if (strncmp(connector_name, edidname, colon - edidname))
+				continue;
+			edidname = colon + 1;
+			break;
+		}
+
+		if (*edidname != '\0') /* corner case: multiple ',' */
+			fallback = edidname;
+	}
+
+	if (!edidname) {
+		if (!fallback) {
+			kfree(fwstr);
 			return 0;
+		}
+		edidname = fallback;
 	}
 
 	last = edidname + strlen(edidname) - 1;
@@ -285,6 +308,8 @@ int drm_load_edid_firmware(struct drm_connector *connector)
 		*last = '\0';
 
 	edid = edid_load(connector, edidname, connector_name);
+	kfree(fwstr);
+
 	if (IS_ERR_OR_NULL(edid))
 		return 0;