Gitweb:
http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=4221d014ea04d439e6d1e65951c3b406e7c1b7ab
Commit: 4221d014ea04d439e6d1e65951c3b406e7c1b7ab
Parent: 3b42d28b2a04b3c9830eb865288239d45eccc402
Author: H. Peter Anvin <[EMAIL PROTECTED]>
AuthorDate: Fri Aug 31 11:30:31 2007 -0700
Committer: H. Peter Anvin <[EMAIL PROTECTED]>
CommitDate: Fri Aug 31 11:52:35 2007 -0700
[x86 setup] Don't rely on the VESA BIOS being register-clean
The VESA BIOS is specified to be register-clean. However, we have now
found at least one system which violates that. Thus, be as paranoid
about VESA calls as about everything else.
Huge thanks to Will Simoneau for reporting, diagnosing, and testing
this out on Dell Inspiron 5150.
Cc: Will Simoneau <[EMAIL PROTECTED]>
Signed-off-by: H. Peter Anvin <[EMAIL PROTECTED]>
---
arch/i386/boot/video-vesa.c | 34 +++++++++++++++++++++-------------
1 files changed, 21 insertions(+), 13 deletions(-)
diff --git a/arch/i386/boot/video-vesa.c b/arch/i386/boot/video-vesa.c
index f1bc71e..1921907 100644
--- a/arch/i386/boot/video-vesa.c
+++ b/arch/i386/boot/video-vesa.c
@@ -29,7 +29,7 @@ static void vesa_store_mode_params_graphics(void);
static int vesa_probe(void)
{
#if defined(CONFIG_VIDEO_VESA) || defined(CONFIG_FIRMWARE_EDID)
- u16 ax;
+ u16 ax, cx, di;
u16 mode;
addr_t mode_ptr;
struct mode_info *mi;
@@ -39,9 +39,11 @@ static int vesa_probe(void)
vginfo.signature = VBE2_MAGIC;
- /* Optimistically assume a VESA BIOS is register-clean... */
ax = 0x4f00;
- asm("int $0x10" : "+a" (ax), "=m" (vginfo) : "D" (&vginfo));
+ di = (size_t)&vginfo;
+ asm(INT10
+ : "+a" (ax), "+D" (di), "=m" (vginfo)
+ : : "ebx", "ecx", "edx", "esi");
if (ax != 0x004f ||
vginfo.signature != VESA_MAGIC ||
@@ -64,9 +66,11 @@ static int vesa_probe(void)
memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
ax = 0x4f01;
- asm("int $0x10"
- : "+a" (ax), "=m" (vminfo)
- : "c" (mode), "D" (&vminfo));
+ cx = mode;
+ di = (size_t)&vminfo;
+ asm(INT10
+ : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
+ : : "ebx", "edx", "esi");
if (ax != 0x004f)
continue;
@@ -102,16 +106,18 @@ static int vesa_probe(void)
static int vesa_set_mode(struct mode_info *mode)
{
- u16 ax;
+ u16 ax, bx, cx, di;
int is_graphic;
u16 vesa_mode = mode->mode - VIDEO_FIRST_VESA;
memset(&vminfo, 0, sizeof vminfo); /* Just in case... */
ax = 0x4f01;
- asm("int $0x10"
- : "+a" (ax), "=m" (vminfo)
- : "c" (vesa_mode), "D" (&vminfo));
+ cx = vesa_mode;
+ di = (size_t)&vminfo;
+ asm(INT10
+ : "+a" (ax), "+c" (cx), "+D" (di), "=m" (vminfo)
+ : : "ebx", "edx", "esi");
if (ax != 0x004f)
return -1;
@@ -129,9 +135,11 @@ static int vesa_set_mode(struct mode_info *mode)
ax = 0x4f02;
- asm volatile("int $0x10"
- : "+a" (ax)
- : "b" (vesa_mode), "D" (0));
+ bx = vesa_mode;
+ di = 0;
+ asm volatile(INT10
+ : "+a" (ax), "+b" (bx), "+D" (di)
+ : : "ecx", "edx", "esi");
if (ax != 0x004f)
return -1;
-
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