桌面应用——宽屏笔记本，915GM芯片组，Linux的设置

为宽屏的分辩率率一和普通屏的不一样，如：1280*768，一些厂家的linux还不支持这些非传统标准的分辨率！
这几天天天在老外的论坛里转，终于第一时间看到for 915GM的video BIOS修改程序，可以直接修改内存里有mode line叁数，让系统支持宽屏显示！
另也找到了，最新的915GM的驱动，经过第三方修改的（奇怪的是Intel提供的不能正常工作，第三方的倒是可以，有了它才能真正发挥915GM的显示能力啊，那个vesa的驱动，太慢了，呵呵）

因这里不好上传附件，只能把原码贴上来了，是那个支持宽屏的修正程序，自己编译一下，如下：
#gcc 915resolution.c -o 915resolution
然后运行 915resolution 5c 1280*768

然后写一脚本，让系统每次启动自动运行！呵呵！

915GM的驱动，大了点，不好贴上来，需要的朋友加我QQ，传给你！


#include
#include
#include
#define __USE_GNU
#include
#include
#include
#include
#include
#include



#define NEW(a) ((a *)(calloc(1, sizeof(a))))
#define FREE(a) (free(a))

#define VBIOS_START 0xc0000
#define VBIOS_SIZE 0x10000

#define VBIOS_FILE "/dev/mem"
#define VBIOS_OFFSET_IN_FILE VBIOS_START

#define CFG_SIGNATURE "BIOS_DATA_BLOCK "

#define FALSE 0
#define TRUE 1

typedef unsigned char * address;
typedef unsigned char boolean;

typedef struct {
unsigned char mode;
unsigned char bits_per_pixel;
unsigned short resolution;
unsigned char unknown;
} __attribute__((packed)) vbios_mode;

typedef struct {
unsigned char unknow1[2];
unsigned char x1;
unsigned char unknow2;
unsigned char x2;
unsigned char y1;
unsigned char unknow3;
unsigned char y2;
} __attribute__((packed)) vbios_resolution;


typedef struct {
int bios_fd;
address bios_ptr;

address cnfg_ptr;

vbios_mode * mode_table;
int mode_table_size;

boolean unlocked;
} vbios_map;


void initialize_system();
char * get_chipset(void);

vbios_map * open_vbios();
void close_vbios(vbios_map * map);

void unlock_vbios(vbios_map * map);
void relock_vbios(vbios_map * map);



void initialize_system(void) {
if (iopl(3) < 0) {
perror("Unable to obtain the proper IO permissions");
exit(2);
}
}

static unsigned int get_chipset_id(void) {
outl(0x80000000, 0xcf8);
return inl(0xcfc);
}

static char chipset_buffer[256];

char * get_chipset(void) {
unsigned int id;
char * name;

id = get_chipset_id();

switch (id) {
case 0x25608086:
name = "845G";
break;

case 0x35808086:
name = "855GM";
break;

case 0x25708086:
name = "865G";
break;

case 0x25908086:
name = "915GM";
break;

default:
sprintf(chipset_buffer, "Unknown (0x%08x)", id);
name = chipset_buffer;
break;
}

return name;
}


vbios_map * open_vbios() {
vbios_map * map = NEW(vbios_map);

/*
* Map the video bios to memory
*/

map->bios_fd = open(VBIOS_FILE, O_RDWR);
if(map->bios_fd < 0) {
perror("Unable to open the BIOS file");
exit(2);
}

map->bios_ptr = mmap((void *)VBIOS_START, VBIOS_SIZE,
PROT_READ | PROT_WRITE, MAP_SHARED | MAP_FIXED,
map->bios_fd, VBIOS_OFFSET_IN_FILE);

if (map->bios_ptr == NULL) {
fprintf(stderr, "Cannot mmap() the video BIOS\n");
close(map->bios_fd);
exit(2);
}

/*
* figure out where the configuration information is
*/

map->cnfg_ptr = memmem(map->bios_ptr, VBIOS_SIZE, CFG_SIGNATURE, strlen(CFG_SIGNATURE));

if (map->cnfg_ptr == NULL) {
fprintf(stderr, "Couldn't find the configuration area in the VBIOS!\n");
close_vbios(map);
exit(2);
}

/*
* Figure out where the mode table is and which type of bios we have
*/

{
address p = map->bios_ptr;
address limit = map->bios_ptr + VBIOS_SIZE - (3 * sizeof(vbios_mode));

while (p < limit && map->mode_table == 0) {
vbios_mode * mode_ptr = (vbios_mode *) p;

if (((mode_ptr[0].mode & 0xf0) == 0x30) && ((mode_ptr[1].mode & 0xf0) == 0x30) &&
((mode_ptr[2].mode & 0xf0) == 0x30) && ((mode_ptr[3].mode & 0xf0) == 0x30)) {

map->mode_table = mode_ptr;
}

p++;
}

if (map->mode_table == 0) {
fprintf(stderr, "Unable to locate mode table!\n");
close_vbios(map);
exit(2);
}
}

/*
* Determine size of mode table
*/

{
vbios_mode * mode_ptr = map->mode_table;

while (mode_ptr->mode != 0xff) {
map->mode_table_size++;
mode_ptr++;
}
}


return map;
}

void close_vbios(vbios_map * map) {
assert(!map->unlocked);

if(map->bios_ptr == NULL) {
fprintf(stderr, "BIOS should be open already!\n");
exit(2);
}

munmap(map->bios_ptr, VBIOS_SIZE);
close(map->bios_fd);

FREE(map);
}

void unlock_vbios(vbios_map * map) {
assert(!map->unlocked);

map->unlocked = TRUE;

outl(0x80000090, 0xcf8);

#if DEBUG
{
unsigned int t = inl(0xcfc);
printf("unlock PAM: (0x%08x)\n", t);
}
#endif

outb(0x33, 0xcfd);
outb(0x33, 0xcfe);

#if DEBUG
{
unsigned int t = inl(0xcfc);
printf("unlock PAM: (0x%08x)\n", t);
}
#endif

}

void relock_vbios(vbios_map * map) {
assert(map->unlocked);

map->unlocked = FALSE;

outl(0x80000090, 0xcf8);

#if DEBUG
{
unsigned int t = inl(0xcfc);
printf("relock PAM: (0x%08x)\n", t);
}
#endif

outb(0x11, 0xcfd);
outb(0x11, 0xcfe);

#if DEBUG
{
unsigned int t = inl(0xcfc);
printf("relock PAM: (0x%08x)\n", t);
}
#endif
}


vbios_resolution * map_resolution(vbios_map * map, unsigned short res) {

vbios_resolution * ptr = ((vbios_resolution*)(map->bios_ptr + res));

return ptr;
}


void list_modes(vbios_map *map) {
unsigned int i, x, y;

for (i=0; i < map->mode_table_size; i++) {
vbios_resolution * res = map_resolution(map, map->mode_table[i].resolution);

x = ((((unsigned int) res->x2) & 0xf0) << 4) | res->x1;
y = ((((unsigned int) res->y2) & 0xf0) << 4) | res->y1;

if (x != 0 && y != 0) {
printf("Mode %02x : %dx%d, %d bits/pixel\n", map->mode_table[i].mode, x, y, map->mode_table[i].bits_per_pixel);
}
}
}


void set_mode(vbios_map * map, unsigned int mode, unsigned int x, unsigned int y) {
unsigned int i;


for (i=0; i < map->mode_table_size; i++) {
if (map->mode_table[i].mode == mode) {
vbios_resolution * res = map_resolution(map, map->mode_table[i].resolution);

res->x2 = (res->x2 & 0x0f) | ((x >> 4) & 0xf0);
res->x1 = (x & 0xff);

res->y2 = (res->y2 & 0x0f) | ((y >> 4) & 0xf0);
res->y1 = (y & 0xff);
}
}


}

int parse_args(int argc, char *argv[], int *list, int *mode, int *x, int *y) {
int index = 1;

*list = *mode = *x = *y = 0;

if ((argc > index) && !strcmp(argv[index], "-l")) {
*list = 1;
index++;

if(argc<=index) {
return 0;
}
}

if(argc-index != 3) {
return -1;
}

*mode = (int) strtol(argv[index], NULL, 16);
*x = atoi(argv[index+1]);
*y = atoi(argv[index+2]);

return 0;
}

void usage(char *name) {
printf("Usage: %s [-l] [mode X Y]\n", name);
printf(" Set the resolution to XxY for mode\n");
printf(" Options:\n");
printf(" -l display the modes found into the vbios\n");
}

int main (int argc, char *argv[]) {
vbios_map * map;
char * chipset;
int list, mode, x, y;

printf("Intel 915GM VBIOS Hack : version 0.1\n\n");

if (parse_args(argc, argv, &list, &mode, &x, &y) == -1) {
usage(argv[0]);
return 2;
}

initialize_system();

chipset = get_chipset();

printf("Chipset: %s\n", chipset);

map = open_vbios();

printf("\n");

if (list) {
list_modes(map);
}

if (mode!=0 && x!=0 && y!=0) {
unlock_vbios(map);
set_mode(map, mode, x, y);
relock_vbios(map);

printf("** Patch mode %02x to resolution %dx%d complete\n", mode, x, y);

if (list) {
list_modes(map);
}
}

close_vbios(map);

return 0;
}

原文转自：http://www.ltesting.net