1 /* -*- linux-c -*- ------------------------------------------------------- *
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright 2007 rPath, Inc. - All Rights Reserved
6 * Original APM BIOS checking by Stephen Rothwell, May 1994
7 * (sfr@canb.auug.org.au)
9 * This file is part of the Linux kernel, and is made available under
10 * the terms of the GNU General Public License version 2.
12 * ----------------------------------------------------------------------- */
15 * arch/i386/boot/apm.c
17 * Get APM BIOS information
22 #if defined(CONFIG_APM) || defined(CONFIG_APM_MODULE)
24 int query_apm_bios(void)
26 u16 ax, bx, cx, dx, di;
30 /* APM BIOS installation check */
33 asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0"
34 : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx)
38 return -1; /* No APM BIOS */
40 if (bx != 0x504d) /* "PM" signature */
43 if (cx & 0x02) /* 32 bits supported? */
46 /* Disconnect first, just in case */
48 asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp"
50 : : "ebx", "ecx", "edx", "esi", "edi");
57 asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %6"
58 : "=a" (ax), "+b" (ebx), "+c" (cx), "+d" (dx),
59 "+S" (esi), "+D" (di), "=m" (err)
62 boot_params.apm_bios_info.cseg = ax;
63 boot_params.apm_bios_info.offset = ebx;
64 boot_params.apm_bios_info.cseg_16 = cx;
65 boot_params.apm_bios_info.dseg = dx;
66 boot_params.apm_bios_info.cseg_len = (u16)esi;
67 boot_params.apm_bios_info.cseg_16_len = esi >> 16;
68 boot_params.apm_bios_info.dseg_len = di;
73 /* Redo the installation check as the 32-bit connect;
74 some BIOSes return different flags this way... */
78 asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp ; setc %0"
79 : "=d" (err), "+a" (ax), "+b" (bx), "+c" (cx)
82 if (err || bx != 0x504d) {
83 /* Failure with 32-bit connect, try to disconect and ignore */
86 asm volatile("pushl %%ebp ; int $0x15 ; popl %%ebp"
87 : "+a" (ax), "+b" (bx)
88 : : "ecx", "edx", "esi", "edi");
92 boot_params.apm_bios_info.version = ax;
93 boot_params.apm_bios_info.flags = cx;