Commit be832f78 authored Oct 19, 2021 by Geert Uytterhoeven Committed by Greg Kroah-Hartman Nov 17, 2021

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@protonic.nl>
Suggested-by: Robin van der Gracht <robin@protonic.nl>
Fixes: 8992da44 ("auxdisplay: ht16k33: Driver for LED controller")
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

parent c4419430

drivers/auxdisplay/ht16k33.c

+10 −0

Original line number	Diff line number	Diff line
		@@ -219,6 +219,15 @@ 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;
		@@ -231,6 +240,7 @@ 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,