viafb: fix rmmod bug

This fixes a bug caused by changing pointers (viafb_mode, viafb_mode1)
assigned by module_param. It reduces driver complexity by not needlessly
changing these vars as they are only read once and removing now
superfluous code.

On unpatched kernels loading viafb with viafb_mode or viafb_mode1 option
used and afterwards unloading it results in:

kernel BUG at mm/slub.c:2926!
invalid opcode: 0000 [#1] PREEMPT
last sysfs file: /sys/devices/virtual/block/loop0/removable
Modules linked in: snd_hda_codec_realtek snd_hda_intel snd_hda_codec
snd_hwdep snd_pcm rtl8187 snd_timer eeprom_93cx6 mmc_block snd soundcore
via_sdmmc fb snd_page_alloc i2c_algo_bit i2c_viapro ehci_hcd uhci_hcd
cfbcopyarea mmc_core cfbimgblt cfbfillrect video output [last unloaded:
viafb]

Pid: 3355, comm: rmmod Not tainted (2.6.31-rc1 #0)
EIP: 0060:[<c106a759>] EFLAGS: 00010246 CPU: 0
EIP is at kfree+0x80/0xda
EAX: c17c2da0 EBX: dc7edbdc ECX: 0000010f EDX: 00000000
ESI: c102c700 EDI: dc7ed8fa EBP: d703ff2c ESP: d703ff20
DS: 007b ES: 007b FS: 0000 GS: 0033 SS: 0068
Process rmmod (pid: 3355, ti=d703e000 task=db1412c0 task.ti=d703e000)
Stack:
dc7edbdc 00000014 00000016 d703ff40 c102c700 dc7f45d4 dc7f45d4 00000880
d703ff4c c103e571 00000000 d703ffac c103e751 66616976 da140062 db89ba80
00000328 d702edf8 db89ba80 d703ff9c c105d0f0 00000200 da14f898 00000014
Call Trace:
[<c102c700>] ? destroy_params+0x1e/0x2b
[<c103e571>] ? free_module+0xa2/0xd7
[<c103e751>] ? sys_delete_module+0x1ab/0x1da
[<c105d0f0>] ? do_munmap+0x20a/0x225
[<c10029b4>] ? sysenter_do_call+0x12/0x26
Code: 10 76 7a 8d 87 00 00 00 40 c1 e8 0c c1 e0 05 03 05 1c 87 41 c1 66 83 38 00 79 03 8b 40 0c 8b 10 84 d2 78 12 66 f7 c2 00 c0 75 04 <0f> 0b eb fe e8 6f 5a fe ff eb 47 8b 55 04 8b 58 0c 9c 5e fa 3b
EIP: [<c106a759>] kfree+0x80/0xda SS:ESP 0068:d703ff20

This is caused by the current code changing the pointers assigned by
module_param. During unload it tries to free the memory the pointers
point at which is now part of an internal structure.

The patch simply avoids changing the pointers. This is okay as they are
read only once during the initialization process.

Signed-off-by: Florian Tobias Schandinat <[e-mail]>
Cc: Scott Fang <[e-mail]>
Cc: Joseph Chan <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

drivers/video/via/hw.c

···
 			viafb_dvi_set_mode(viafb_get_mode_index
 				     (viaparinfo->tmds_setting_info->h_active,
 				      viaparinfo->tmds_setting_info->
-				      v_active, 1),
+				      v_active),
 				     video_bpp1, viaparinfo->
 				     tmds_setting_info->iga_path);
 		} else {
 			viafb_dvi_set_mode(viafb_get_mode_index
 				     (viaparinfo->tmds_setting_info->h_active,
 				      viaparinfo->
-				      tmds_setting_info->v_active, 0),
+				      tmds_setting_info->v_active),
 				     video_bpp, viaparinfo->
 				     tmds_setting_info->iga_path);
 		}

drivers/video/via/lcd.c

···
 	int reg_num = 0;
 	struct io_reg *lcd_patch_reg = NULL;
 
-	if (viaparinfo->lvds_setting_info->iga_path == IGA2)
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 1);
-	else
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 0);
+	vmode_index = viafb_get_mode_index(set_hres, set_vres);
 	switch (panel_id) {
 		/* LCD 800x600 */
 	case LCD_PANEL_ID1_800X600:
···
 	int reg_num = 0;
 	struct io_reg *lcd_patch_reg = NULL;
 
-	if (viaparinfo->lvds_setting_info->iga_path == IGA2)
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 1);
-	else
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 0);
+	vmode_index = viafb_get_mode_index(set_hres, set_vres);
 
 	switch (panel_id) {
 	case LCD_PANEL_ID5_1400X1050:
···
 {
 	int vmode_index;
 
-	if (viaparinfo->lvds_setting_info->iga_path == IGA2)
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 1);
-	else
-		vmode_index = viafb_get_mode_index(set_hres, set_vres, 0);
+	vmode_index = viafb_get_mode_index(set_hres, set_vres);
 
 	viafb_unlock_crt();
 

drivers/video/via/viafbdev.c

···
 /* video mode */
 static char *viafb_mode = "640x480";
 static char *viafb_mode1 = "640x480";
-static int viafb_resMode = VIA_RES_640X480;
 
 /* Added for specifying active devices.*/
 char *viafb_active_dev = "";
···
 
 /* Mode information */
 static const struct viafb_modeinfo viafb_modentry[] = {
-	{480, 640, VIA_RES_480X640, "480x640"},
-	{640, 480, VIA_RES_640X480, "640x480"},
-	{800, 480, VIA_RES_800X480, "800x480"},
-	{800, 600, VIA_RES_800X600, "800x600"},
-	{1024, 768, VIA_RES_1024X768, "1024x768"},
-	{1152, 864, VIA_RES_1152X864, "1152x864"},
-	{1280, 1024, VIA_RES_1280X1024, "1280x1024"},
-	{1600, 1200, VIA_RES_1600X1200, "1600x1200"},
-	{1440, 1050, VIA_RES_1440X1050, "1440x1050"},
-	{1280, 768, VIA_RES_1280X768, "1280x768"},
-	{1280, 800, VIA_RES_1280X800, "1280x800"},
-	{1280, 960, VIA_RES_1280X960, "1280x960"},
-	{1920, 1440, VIA_RES_1920X1440, "1920x1440"},
-	{848, 480, VIA_RES_848X480, "848x480"},
-	{1400, 1050, VIA_RES_1400X1050, "1400x1050"},
-	{720, 480, VIA_RES_720X480, "720x480"},
-	{720, 576, VIA_RES_720X576, "720x576"},
-	{1024, 512, VIA_RES_1024X512, "1024x512"},
-	{1024, 576, VIA_RES_1024X576, "1024x576"},
-	{1024, 600, VIA_RES_1024X600, "1024x600"},
-	{1280, 720, VIA_RES_1280X720, "1280x720"},
-	{1920, 1080, VIA_RES_1920X1080, "1920x1080"},
-	{1366, 768, VIA_RES_1368X768, "1368x768"},
-	{1680, 1050, VIA_RES_1680X1050, "1680x1050"},
-	{960, 600, VIA_RES_960X600, "960x600"},
-	{1000, 600, VIA_RES_1000X600, "1000x600"},
-	{1024, 576, VIA_RES_1024X576, "1024x576"},
-	{1024, 600, VIA_RES_1024X600, "1024x600"},
-	{1088, 612, VIA_RES_1088X612, "1088x612"},
-	{1152, 720, VIA_RES_1152X720, "1152x720"},
-	{1200, 720, VIA_RES_1200X720, "1200x720"},
-	{1280, 600, VIA_RES_1280X600, "1280x600"},
-	{1360, 768, VIA_RES_1360X768, "1360x768"},
-	{1440, 900, VIA_RES_1440X900, "1440x900"},
-	{1600, 900, VIA_RES_1600X900, "1600x900"},
-	{1600, 1024, VIA_RES_1600X1024, "1600x1024"},
-	{1792, 1344, VIA_RES_1792X1344, "1792x1344"},
-	{1856, 1392, VIA_RES_1856X1392, "1856x1392"},
-	{1920, 1200, VIA_RES_1920X1200, "1920x1200"},
-	{2048, 1536, VIA_RES_2048X1536, "2048x1536"},
-	{0, 0, VIA_RES_INVALID, "640x480"}
+	{480, 640, VIA_RES_480X640},
+	{640, 480, VIA_RES_640X480},
+	{800, 480, VIA_RES_800X480},
+	{800, 600, VIA_RES_800X600},
+	{1024, 768, VIA_RES_1024X768},
+	{1152, 864, VIA_RES_1152X864},
+	{1280, 1024, VIA_RES_1280X1024},
+	{1600, 1200, VIA_RES_1600X1200},
+	{1440, 1050, VIA_RES_1440X1050},
+	{1280, 768, VIA_RES_1280X768,},
+	{1280, 800, VIA_RES_1280X800},
+	{1280, 960, VIA_RES_1280X960},
+	{1920, 1440, VIA_RES_1920X1440},
+	{848, 480, VIA_RES_848X480},
+	{1400, 1050, VIA_RES_1400X1050},
+	{720, 480, VIA_RES_720X480},
+	{720, 576, VIA_RES_720X576},
+	{1024, 512, VIA_RES_1024X512},
+	{1024, 576, VIA_RES_1024X576},
+	{1024, 600, VIA_RES_1024X600},
+	{1280, 720, VIA_RES_1280X720},
+	{1920, 1080, VIA_RES_1920X1080},
+	{1366, 768, VIA_RES_1368X768},
+	{1680, 1050, VIA_RES_1680X1050},
+	{960, 600, VIA_RES_960X600},
+	{1000, 600, VIA_RES_1000X600},
+	{1024, 576, VIA_RES_1024X576},
+	{1024, 600, VIA_RES_1024X600},
+	{1088, 612, VIA_RES_1088X612},
+	{1152, 720, VIA_RES_1152X720},
+	{1200, 720, VIA_RES_1200X720},
+	{1280, 600, VIA_RES_1280X600},
+	{1360, 768, VIA_RES_1360X768},
+	{1440, 900, VIA_RES_1440X900},
+	{1600, 900, VIA_RES_1600X900},
+	{1600, 1024, VIA_RES_1600X1024},
+	{1792, 1344, VIA_RES_1792X1344},
+	{1856, 1392, VIA_RES_1856X1392},
+	{1920, 1200, VIA_RES_1920X1200},
+	{2048, 1536, VIA_RES_2048X1536},
+	{0, 0, VIA_RES_INVALID}
 };
 
 static struct fb_ops viafb_ops;
···
 	if (var->vmode & FB_VMODE_INTERLACED || var->vmode & FB_VMODE_DOUBLE)
 		return -EINVAL;
 
-	vmode_index = viafb_get_mode_index(var->xres, var->yres, 0);
+	vmode_index = viafb_get_mode_index(var->xres, var->yres);
 	if (vmode_index == VIA_RES_INVALID) {
 		DEBUG_MSG(KERN_INFO
 			  "viafb: Mode %dx%dx%d not supported!!\n",
···
 	viafb_update_device_setting(info->var.xres, info->var.yres,
 			      info->var.bits_per_pixel, viafb_refresh, 0);
 
-	vmode_index = viafb_get_mode_index(info->var.xres, info->var.yres, 0);
+	vmode_index = viafb_get_mode_index(info->var.xres, info->var.yres);
 
 	if (viafb_SAMM_ON == 1) {
 		DEBUG_MSG(KERN_INFO
 		"viafb_second_xres = %d, viafb_second_yres = %d, bpp = %d\n",
 			  viafb_second_xres, viafb_second_yres, viafb_bpp1);
 		vmode_index1 = viafb_get_mode_index(viafb_second_xres,
-			viafb_second_yres, 1);
+			viafb_second_yres);
 		DEBUG_MSG(KERN_INFO "->viafb_SAMM_ON: index=%d\n",
 			vmode_index1);
 
···
 	return 0;
 }
 
-int viafb_get_mode_index(int hres, int vres, int flag)
+int viafb_get_mode_index(int hres, int vres)
 {
 	u32 i;
 	DEBUG_MSG(KERN_INFO "viafb_get_mode_index!\n");
···
 			viafb_modentry[i].yres == vres)
 			break;
 
-	viafb_resMode = viafb_modentry[i].mode_index;
-	if (flag)
-		viafb_mode1 = viafb_modentry[i].mode_res;
-	else
-		viafb_mode = viafb_modentry[i].mode_res;
-
-	return viafb_resMode;
+	return viafb_modentry[i].mode_index;
 }
 
 static void check_available_device_to_enable(int device_id)
···
 	strict_strtoul(tmpc, 0, &default_xres);
 	strict_strtoul(tmpm, 0, &default_yres);
 
-	vmode_index = viafb_get_mode_index(default_xres, default_yres, 0);
+	vmode_index = viafb_get_mode_index(default_xres, default_yres);
 	DEBUG_MSG(KERN_INFO "0->index=%d\n", vmode_index);
 
 	if (viafb_SAMM_ON == 1) {

drivers/video/via/viafbdev.h

···
 	u32 xres;
 	u32 yres;
 	int mode_index;
-	char *mode_res;
 };
 extern unsigned int viafb_second_virtual_yres;
 extern unsigned int viafb_second_virtual_xres;
···
 void viafb_memory_pitch_patch(struct fb_info *info);
 void viafb_fill_var_timing_info(struct fb_var_screeninfo *var, int refresh,
 			  int mode_index);
-int viafb_get_mode_index(int hres, int vres, int flag);
+int viafb_get_mode_index(int hres, int vres);
 u8 viafb_gpio_i2c_read_lvds(struct lvds_setting_information
 	*plvds_setting_info, struct lvds_chip_information
 	*plvds_chip_info, u8 index);