The vga16fb framebuffer driver only supports Enhanced Graphics Adapter (EGA) and Video Graphics Array (VGA) 16 color graphic cards.
But it doesn't check if the adapter is one of those or if a VGA16 mode is used. This means that the driver will be probed even if a VESA BIOS Extensions (VBE) or Graphics Output Protocol (GOP) interface is used.
This issue has been present for a long time but it was only exposed by commit d391c5827107 ("drivers/firmware: move x86 Generic System Framebuffers support") since the platform device registration to match the {vesa,efi}fb drivers is done later as a consequence of that change.
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215001 Fixes: d391c5827107 ("drivers/firmware: move x86 Generic System Framebuffers support") Reported-by: Kris Karas bugs-a21@moonlit-rail.com Cc: stable@vger.kernel.org # 5.15.x Signed-off-by: Javier Martinez Canillas javierm@redhat.com Tested-by: Kris Karas bugs-a21@moonlit-rail.com ---
drivers/video/fbdev/vga16fb.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/video/fbdev/vga16fb.c b/drivers/video/fbdev/vga16fb.c index 3347c9b6a332..72b6aeceeff8 100644 --- a/drivers/video/fbdev/vga16fb.c +++ b/drivers/video/fbdev/vga16fb.c @@ -1422,6 +1422,18 @@ static int __init vga16fb_init(void)
vga16fb_setup(option); #endif + + /* only EGA and VGA in 16 color graphic mode are supported */ + if (screen_info.orig_video_isVGA != VIDEO_TYPE_EGAC && + screen_info.orig_video_isVGA != VIDEO_TYPE_VGAC) + return -ENODEV; + + if (screen_info.orig_video_mode != 0x0D && /* 320x200/4 (EGA) */ + screen_info.orig_video_mode != 0x0E && /* 640x200/4 (EGA) */ + screen_info.orig_video_mode != 0x10 && /* 640x350/4 (EGA) */ + screen_info.orig_video_mode != 0x12) /* 640x480/4 (VGA) */ + return -ENODEV; + ret = platform_driver_register(&vga16fb_driver);
if (!ret) {