This is a note to let you know that I've just added the patch titled
auxdisplay: ht16k33: Fix frame buffer device blanking
to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
auxdisplay-ht16k33-fix-frame-buffer-device-blanking.patch
and it can be found in the queue-4.14 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 6715e58c5264f17cd45f8bca51951c81de0a31d2
Author: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Date: Tue Oct 19 16:45:09 2021 +0200
auxdisplay: ht16k33: Fix frame buffer device blanking
[ Upstream commit 840fe258332544aa7321921e1723d37b772af7a9 ]
As the ht16k33 frame buffer sub-driver does not register an
fb_ops.fb_blank() handler, blanking does not work:
$ echo 1 > /sys/class/graphics/fb0/blank
sh: write error: Invalid argument
Fix this by providing a handler that always returns zero, to make sure
blank events will be sent to the actual device handling the backlight.
Reported-by: Robin van der Gracht <robin@xxxxxxxxxxx>
Suggested-by: Robin van der Gracht <robin@xxxxxxxxxxx>
Fixes: 8992da44c6805d53 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
Signed-off-by: Miguel Ojeda <ojeda@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index e3c8f355f9a62..f35b7ff29efd2 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -227,6 +227,15 @@ static const struct backlight_ops ht16k33_bl_ops = {
.check_fb = ht16k33_bl_check_fb,
};
+/*
+ * Blank events will be passed to the actual device handling the backlight when
+ * we return zero here.
+ */
+static int ht16k33_blank(int blank, struct fb_info *info)
+{
+ return 0;
+}
+
static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
struct ht16k33_priv *priv = info->par;
@@ -239,6 +248,7 @@ static struct fb_ops ht16k33_fb_ops = {
.owner = THIS_MODULE,
.fb_read = fb_sys_read,
.fb_write = fb_sys_write,
+ .fb_blank = ht16k33_blank,
.fb_fillrect = sys_fillrect,
.fb_copyarea = sys_copyarea,
.fb_imageblit = sys_imageblit,
