This is a note to let you know that I've just added the patch titled
drm/bochs: fix blanking
to the 5.19-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:
drm-bochs-fix-blanking.patch
and it can be found in the queue-5.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d8883f13ba12811d6b81ed1b66547b2aa230b5c4
Author: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Date: Tue Sep 6 16:29:57 2022 +0200
drm/bochs: fix blanking
[ Upstream commit e740ceb53e4579a7a4063712cebecac3c343b189 ]
VGA_IS1_RC is the color mode register (VGA_IS1_RM the one for monochrome
mode, note C vs. M at the end). So when using VGA_IS1_RC make sure the
vga device is actually in color mode and set the corresponding bit in the
misc register.
Reproducible when booting VMs in UEFI mode with some edk2 versions (edk2
fix is on the way too). Doesn't happen in BIOS mode because in that
case the vgabios already flips the bit.
Fixes: 250e743915d4 ("drm/bochs: Add screen blanking support")
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20220906142957.2763577-1-kraxel@xxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/tiny/bochs.c b/drivers/gpu/drm/tiny/bochs.c
index ed971c8bb446..0cedb6f6f559 100644
--- a/drivers/gpu/drm/tiny/bochs.c
+++ b/drivers/gpu/drm/tiny/bochs.c
@@ -306,6 +306,8 @@ static void bochs_hw_fini(struct drm_device *dev)
static void bochs_hw_blank(struct bochs_device *bochs, bool blank)
{
DRM_DEBUG_DRIVER("hw_blank %d\n", blank);
+ /* enable color bit (so VGA_IS1_RC access works) */
+ bochs_vga_writeb(bochs, VGA_MIS_W, VGA_MIS_COLOR);
/* discard ar_flip_flop */
(void)bochs_vga_readb(bochs, VGA_IS1_RC);
/* blank or unblank; we need only update index and set 0x20 */
