[PATCH] i810fb: Fix oops if CONFIG_FB_I810_I2C is set to no

Reported by: Manuel Lauss <mano@roarinelk.homelinux.net>

compiled with CONFIG_FB_I810_I2C = n and CONFIG_FB_I810 = y
it oopses at boot in file drivers/video/i810/i810_main.c:1884

...
Unable to handle kernel NULL pointer dereference at virtual address 00000054
printing eip:
c02543c0
*pde = 00000000
Oops: 0000 [#1]
last sysfs file:
Modules linked in:
CPU:    0
EIP:    0060:[<c02543c0>]    Not tainted VLI
EFLAGS: 00010286   (2.6.13-mm2)
EIP is at i810fb_find_init_mode+0x53/0x93
eax: c113ddd4   ebx: c1194000   ecx: c04be2dd   edx: c1194000
esi: c1194008   edi: c113ddd4   ebp: c1194240   esp: c113ddcc
ds: 007b   es: 007b   ss: 0068

struct fb_monspecs *specs is initialized to NULL causing the oops.

Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

diff --git a/drivers/video/i810/i810_main.c b/drivers/video/i810/i810_main.c
index 7018fff..6f11989 100644 (file)
--- a/drivers/video/i810/i810_main.c
+++ b/drivers/video/i810/i810_main.c
@@ -950,7 +950,7 @@ static int i810_check_params(struct fb_var_screeninfo *var,
                             struct fb_info *info)
 {
        struct i810fb_par *par = (struct i810fb_par *) info->par;
-       int line_length, vidmem, mode_valid = 0;
+       int line_length, vidmem, mode_valid = 0, retval = 0;
        u32 vyres = var->yres_virtual, vxres = var->xres_virtual;
        /*
         *  Memory limit
@@ -1026,10 +1026,11 @@ static int i810_check_params(struct fb_var_screeninfo *var,
                        printk("i810fb: invalid video mode%s\n",
                               default_sync ? "" : ". Specifying "
                               "vsyncN/hsyncN parameters may help");
+                       retval = -EINVAL;
                }
        }
 
-       return 0;
+       return retval;
 }      
 
 /**
@@ -1830,7 +1831,7 @@ static void __devinit i810fb_find_init_mode(struct fb_info *info)
 {
        struct fb_videomode mode;
        struct fb_var_screeninfo var;
-       struct fb_monspecs *specs = NULL;
+       struct fb_monspecs *specs = &info->monspecs;
        int found = 0;
 #ifdef CONFIG_FB_I810_I2C
        int i;
@@ -1853,12 +1854,11 @@ static void __devinit i810fb_find_init_mode(struct fb_info *info)
        if (!err)
                printk("i810fb_init_pci: DDC probe successful\n");
 
-       fb_edid_to_monspecs(par->edid, &info->monspecs);
+       fb_edid_to_monspecs(par->edid, specs);
 
-       if (info->monspecs.modedb == NULL)
+       if (specs->modedb == NULL)
                printk("i810fb_init_pci: Unable to get Mode Database\n");
 
-       specs = &info->monspecs;
        fb_videomode_to_modelist(specs->modedb, specs->modedb_len,
                                 &info->modelist);
        if (specs->modedb != NULL) {