x86/simplefb: Fix overflow causing bogus fall-back

On my MacBook Air lfb_size is 4M, which makes the bitshit
overflow (to 256GB - larger than 32 bits), meaning we fall
back to efifb unnecessarily.

Cast to u64 to avoid the overflow.

Signed-off-by: Tom Gundersen <teg@jklm.no>
Reviewed-by: David Herrmann <dh.herrmann@gmail.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Stephen Warren <swarren@nvidia.com>
Cc: Stephen Warren <swarren@wwwdotorg.org>
Link: http://lkml.kernel.org/r/1380644320-1026-1-git-send-email-teg@jklm.no
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/kernel/sysfb_simplefb.c b/arch/x86/kernel/sysfb_simplefb.c
index 22513e96b0125c54510722afab5f7abab8f73405..4ebd636b04b8fc5276590284a538263305c017b6 100644 (file)
--- a/arch/x86/kernel/sysfb_simplefb.c
+++ b/arch/x86/kernel/sysfb_simplefb.c
@@ -72,7 +72,7 @@ __init int create_simplefb(const struct screen_info *si,
         * the part that is occupied by the framebuffer */
        len = mode->height * mode->stride;
        len = PAGE_ALIGN(len);
-       if (len > si->lfb_size << 16) {
+       if (len > (u64)si->lfb_size << 16) {
                printk(KERN_WARNING "sysfb: VRAM smaller than advertised\n");
                return -EINVAL;
        }