1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  *  (C) 2003  Bruno Ducrot
4  *  (C) 2004  Dominik Brodowski <linux@dominikbrodowski.de>
5  *
6  * Based on code found in
7  * linux/include/asm-i386/ist.h and linux/arch/i386/kernel/setup.c
8  * and originally developed by Andy Grover <andrew.grover@intel.com>
9  */
10 
11 #include <stdio.h>
12 #include <string.h>
13 #include <lrmi.h>
14 
main(void)15 int main (void)
16 {
17 	struct LRMI_regs	r;
18 	int			retval;
19 
20 	if (!LRMI_init())
21 		return 0;
22 
23 	memset(&r, 0, sizeof(r));
24 
25 	r.eax = 0x0000E980;
26 	r.edx = 0x47534943;
27 
28 	retval = LRMI_int(0x15, &r);
29 
30 	if (!retval) {
31 		printf("Failed!\n");
32 		return 0;
33 	}
34 	if (r.eax == 0x47534943) {
35 		printf("BIOS supports GSIC call:\n");
36 		printf("\tsignature: %c%c%c%c\n",
37 		       (r.eax >> 24) & 0xff,
38 		       (r.eax >> 16) & 0xff,
39 		       (r.eax >> 8) & 0xff,
40 		       (r.eax) & 0xff);
41 		printf("\tcommand port = 0x%.4x\n",
42 		       r.ebx & 0xffff);
43 		printf("\tcommand =      0x%.4x\n",
44 		       (r.ebx >> 16) & 0xffff);
45 		printf("\tevent port =   0x%.8x\n", r.ecx);
46 		printf("\tflags =        0x%.8x\n", r.edx);
47 		if (((r.ebx >> 16) & 0xffff) != 0x82) {
48 			printf("non-default command value. If speedstep-smi "
49 			       "doesn't work out of the box,\nyou may want to "
50 			       "try out the default value by passing "
51 			       "smi_cmd=0x82 to the module\n ON YOUR OWN "
52 			       "RISK.\n");
53 		}
54 		if ((r.ebx & 0xffff) != 0xb2) {
55 			printf("non-default command port. If speedstep-smi "
56 			       "doesn't work out of the box,\nyou may want to "
57 			       "try out the default value by passing "
58 			       "smi_port=0x82 to the module\n ON YOUR OWN "
59 			       "RISK.\n");
60 		}
61 	} else {
62 		printf("BIOS DOES NOT support GSIC call.  Dumping registers anyway:\n");
63 		printf("eax = 0x%.8x\n", r.eax);
64 		printf("ebx = 0x%.8x\n", r.ebx);
65 		printf("ecx = 0x%.8x\n", r.ecx);
66 		printf("edx = 0x%.8x\n", r.edx);
67 		printf("Note also that some BIOS do not support the initial "
68 		       "GSIC call, but the newer\nspeedstep-smi driver may "
69 		       "work.\nFor this, you need to pass some arguments to "
70 		       "the speedstep-smi driver:\n");
71 		printf("\tsmi_cmd=0x?? smi_port=0x?? smi_sig=1\n");
72 		printf("\nUnfortunately, you have to know what exactly are "
73 		       "smi_cmd and smi_port, and this\nis system "
74 		       "dependent.\n");
75 	}
76 	return 1;
77 }
78