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>

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 1d6f045..caf0fd4 100644 (file)
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -927,11 +927,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        The filter can be disabled or changed to another
                        driver later using sysfs.
 
-       drm_kms_helper.edid_firmware=[<connector>:]<file>
-                       Broken monitors, graphic adapters and KVMs may
-                       send no or incorrect EDID data sets. This parameter
-                       allows to specify an EDID data set in the
-                       /lib/firmware directory that is used instead.
+       drm_kms_helper.edid_firmware=[<connector>:]<file>[,[<connector>:]<file>]
+                       Broken monitors, graphic adapters, KVMs and EDIDless
+                       panels may send no or incorrect EDID data sets.
+                       This parameter allows to specify an EDID data sets
+                       in the /lib/firmware directory that are used instead.
                        Generic built-in EDID data sets are used, if one of
                        edid/1024x768.bin, edid/1280x1024.bin,
                        edid/1680x1050.bin, or edid/1920x1080.bin is given
@@ -940,7 +940,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                        available in Documentation/EDID/HOWTO.txt. An EDID
                        data set will only be used for a particular connector,
                        if its name and a colon are prepended to the EDID
-                       name.
+                       name. Each connector may use a unique EDID data
+                       set by separating the files with a comma.  An EDID
+                       data set with no connector name will be used for
+                       any connectors not explicitly specified.
 
        dscc4.setup=    [NET]
 

diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
index c5605fe..1f445e9 100644 (file)
--- 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;