From: Gerd Hoffmann kraxel@redhat.com
[ 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@redhat.com Acked-by: Thomas Zimmermann tzimmermann@suse.de Link: http://patchwork.freedesktop.org/patch/msgid/20220906142957.2763577-1-kraxel... Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpu/drm/tiny/bochs.c | 2 ++ 1 file changed, 2 insertions(+)
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 */