fbdev: ignore VESA modes if framebuffer does not support them

Currently, it is possible to set a graphics VESA mode at boot time via the
vga= parameter even when no framebuffer driver supporting this is
configured.  This could lead to the system booting with a black screen,
without a usable console.

Fix this problem by only allowing to set graphics modes at boot time if a
supporting framebuffer driver is configured.

Signed-off-by: Michal Januszewski <spock@gentoo.org>
Acked-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 11 insertions, 0 deletions

diff --git a/drivers/video/Kconfig b/drivers/video/Kconfig
index 3b296e410f91..6210755cf6ab 100644
--- a/drivers/video/Kconfig
+++ b/drivers/video/Kconfig
@@ -76,6 +76,14 @@ config FB_DDC
        select I2C
        default n
 
+config FB_BOOT_VESA_SUPPORT
+        bool
+        depends on FB
+        default n
+        ---help---
+          If true, at least one selected framebuffer driver can take advantage
+          of VESA video modes set at an early boot stage via the vga= parameter.
+
 config FB_CFB_FILLRECT
         tristate
         depends on FB
@@ -681,6 +689,7 @@ config FB_VESA
         select FB_CFB_FILLRECT
         select FB_CFB_COPYAREA
         select FB_CFB_IMAGEBLIT
+        select FB_BOOT_VESA_SUPPORT
         help
           This is the frame buffer device driver for generic VESA 2.0
           compliant graphic cards. The older VESA 1.2 cards are not supported.
@@ -1117,6 +1126,7 @@ config FB_INTEL
         select FB_CFB_FILLRECT
         select FB_CFB_COPYAREA
         select FB_CFB_IMAGEBLIT
+        select FB_BOOT_VESA_SUPPORT
         help
           This driver supports the on-board graphics built in to the Intel
           830M/845G/852GM/855GM/865G/915G/915GM/945G/945GM/965G/965GM chipsets.
@@ -1469,6 +1479,7 @@ config FB_SIS
         select FB_CFB_FILLRECT
         select FB_CFB_COPYAREA
         select FB_CFB_IMAGEBLIT
+        select FB_BOOT_VESA_SUPPORT
         help
           This is the frame buffer device driver for the SiS 300, 315, 330
           and 340 series as well as XGI V3XT, V5, V8, Z7 graphics chipsets.