x86: fix usage of bios intcall()

Some intcall() misuses the input biosregs as output in
cf06de7b9cdd3efee7a59dced1977b3c21d43732

This fixes the problem vga=ask boot option doesn't show enough modes.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
LKML-Reference: <20090701021307.GA3127@localhost.localdomain>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>

2 files changed, 3 insertions, 4 deletions

diff --git a/arch/x86/boot/video-bios.c b/arch/x86/boot/video-bios.c
index d660be492363..49e0c18833e0 100644
--- a/arch/x86/boot/video-bios.c
+++ b/arch/x86/boot/video-bios.c
@@ -37,14 +37,13 @@ static int set_bios_mode(u8 mode)
         ireg.al = mode;         /* AH=0x00 Set Video Mode */
         intcall(0x10, &ireg, NULL);
 
-
         ireg.ah = 0x0f;         /* Get Current Video Mode */
         intcall(0x10, &ireg, &oreg);
 
         do_restore = 1;         /* Assume video contents were lost */
 
         /* Not all BIOSes are clean with the top bit */
-        new_mode = ireg.al & 0x7f;
+        new_mode = oreg.al & 0x7f;
 
         if (new_mode == mode)
                 return 0;       /* Mode change OK */
diff --git a/arch/x86/boot/video-vesa.c b/arch/x86/boot/video-vesa.c
index c700147d6ffb..275dd177f198 100644
--- a/arch/x86/boot/video-vesa.c
+++ b/arch/x86/boot/video-vesa.c
@@ -45,7 +45,7 @@ static int vesa_probe(void)
         ireg.di = (size_t)&vginfo;
         intcall(0x10, &ireg, &oreg);
 
-        if (ireg.ax != 0x004f ||
+        if (oreg.ax != 0x004f ||
             vginfo.signature != VESA_MAGIC ||
             vginfo.version < 0x0102)
                 return 0;       /* Not present */
@@ -70,7 +70,7 @@ static int vesa_probe(void)
                 ireg.di = (size_t)&vminfo;
                 intcall(0x10, &ireg, &oreg);
 
-                if (ireg.ax != 0x004f)
+                if (oreg.ax != 0x004f)
                         continue;
 
                 if ((vminfo.mode_attr & 0x15) == 0x05) {