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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>
This commit is contained in:
Michal Januszewski 2008-10-15 22:03:51 -07:00 committed by Linus Torvalds
parent 5ab4840968
commit 4d31a2b74c
2 changed files with 15 additions and 5 deletions
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9
arch/x86/boot/video-vesa.c
View File

@ -88,14 +88,11 @@ static int vesa_probe(void)
(vminfo.memory_layout == 4 ||
vminfo.memory_layout == 6) &&
vminfo.memory_planes == 1) {
#ifdef CONFIG_FB
#ifdef CONFIG_FB_BOOT_VESA_SUPPORT
/* Graphics mode, color, linear frame buffer
supported. Only register the mode if
if framebuffer is configured, however,
otherwise the user will be left without a screen.
We don't require CONFIG_FB_VESA, however, since
some of the other framebuffer drivers can use
this mode-setting, too. */
otherwise the user will be left without a screen. */
mi = GET_HEAP(struct mode_info, 1);
mi->mode = mode + VIDEO_FIRST_VESA;
mi->depth = vminfo.bpp;
@ -133,10 +130,12 @@ static int vesa_set_mode(struct mode_info *mode)
if ((vminfo.mode_attr & 0x15) == 0x05) {
/* It's a supported text mode */
is_graphic = 0;
#ifdef CONFIG_FB_BOOT_VESA_SUPPORT
} else if ((vminfo.mode_attr & 0x99) == 0x99) {
/* It's a graphics mode with linear frame buffer */
is_graphic = 1;
vesa_mode |= 0x4000; /* Request linear frame buffer */
#endif
} else {
return -1; /* Invalid mode */
}

11
drivers/video/Kconfig
View File

@ -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.