staging: udlfb: support for writing backup EDID to sysfs file
Support writing default/backup edid via /sys/class/graphics/fb?/edid
Writing a backup edid blob to the 'edid' file will cause udlfb to
attempt to re-read the edid from hardware.
If we still don't have a good edid, it will use the backup edid instead.
The intent is to 1) enable user-supplied edid
2) enable udev rules to backup the last known good edid
for a device, and then provide that edid as a backup for all future starts
Signed-off-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/staging/udlfb/udlfb.c b/drivers/staging/udlfb/udlfb.c
index bcb4a1e9..b13869b 100644
--- a/drivers/staging/udlfb/udlfb.c
+++ b/drivers/staging/udlfb/udlfb.c
@@ -1306,6 +1306,29 @@
return count;
}
+static ssize_t edid_store(
+ struct file *filp,
+ struct kobject *kobj, struct bin_attribute *a,
+ char *src, loff_t src_off, size_t src_size) {
+ struct device *fbdev = container_of(kobj, struct device, kobj);
+ struct fb_info *fb_info = dev_get_drvdata(fbdev);
+ struct dlfb_data *dev = fb_info->par;
+
+ /* We only support write of entire EDID at once, no offset*/
+ if ((src_size < MIN_EDID_SIZE) ||
+ (src_size > MAX_EDID_SIZE) ||
+ (src_off != 0))
+ return 0;
+
+ dlfb_setup_modes(dev, fb_info, src, src_size);
+
+ if (dev->edid && (memcmp(src, dev->edid, src_size) == 0)) {
+ dl_info("sysfs written EDID is new default\n");
+ dlfb_ops_set_par(fb_info);
+ return src_size;
+ } else
+ return 0;
+}
static ssize_t metrics_reset_store(struct device *fbdev,
struct device_attribute *attr,
@@ -1348,9 +1371,10 @@
static struct bin_attribute edid_attr = {
.attr.name = "edid",
- .attr.mode = 0444,
- .size = 128,
+ .attr.mode = 0666,
+ .size = MAX_EDID_SIZE,
.read = edid_show,
+ .write = edid_store
};
static struct device_attribute fb_device_attrs[] = {