Re: 2.6.22-rc1-mm1

["young dave" <hidave.darkstar@gmail.com>]

Hi,
> This implies a miscompile somewhere, *or* that your bios stomps on
> registers that gcc expect preserved, and adding printf's disturbs the
> register allocation sufficiently.

I think maybe it's caused by gcc optimize, so I add volatile to
read_sector inline assemblly, then kernel can boot successfully.

please check this patch :

diff -ur linux/arch/i386/boot/edd.c linux.new/arch/i386/boot/edd.c
--- linux/arch/i386/boot/edd.c  2007-05-22 10:08:59.000000000 +0000
+++ linux.new/arch/i386/boot/edd.c      2007-05-22 10:06:24.000000000 +0000
@@ -47,7 +47,7 @@
       ax = 0x4200;            /* Extended Read */
       si = (size_t)&dapa;
       dx = devno;
-       asm ("pushfl; stc; int $0x13; setc %%al; popfl"
+       asm volatile("pushfl; stc; int $0x13; setc %%al; popfl"
           : "+a" (ax), "+S" (si), "+d" (devno)
           : : "ebx", "ecx", "edi");

@@ -58,7 +58,7 @@
       cx = 0x0001;            /* Sector 0-0-1 */
       dx = devno;
       bx = (size_t)buf;
-       asm ("pushfl; stc; int $0x13; setc %%al; popfl"
+       asm volatile("pushfl; stc; int $0x13; setc %%al; popfl"
           : "+a" (ax), "+c" (cx), "+d" (dx), "+b" (bx)
           : : "esi", "edi");

Regards
dave
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