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| author | Wang YanQing <udknight@gmail.com> | 2016-05-05 14:14:21 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2016-05-05 16:01:00 +0200 |
| commit | c10fcb14c7afd6688c7b197a814358fecf244222 (patch) | |
| tree | fc70c2fe4fbb5b974eb7ec07eeec5f409b2fca0c /arch/x86 | |
| parent | 7f9b474c92713067237c8188f32791cc4007b5da (diff) | |
| download | linux-c10fcb14c7afd6688c7b197a814358fecf244222.tar.bz2 | |
x86/sysfb_efi: Fix valid BAR address range check
The code for checking whether a BAR address range is valid will break
out of the loop when a start address of 0x0 is encountered.
This behaviour is wrong since by breaking out of the loop we may miss
the BAR that describes the EFI frame buffer in a later iteration.
Because of this bug I can't use video=efifb: boot parameter to get
efifb on my new ThinkPad E550 for my old linux system hard disk with
3.10 kernel. In 3.10, efifb is the only choice due to DRM/I915 not
supporting the GPU.
This patch also add a trivial optimization to break out after we find
the frame buffer address range without testing later BARs.
Signed-off-by: Wang YanQing <udknight@gmail.com>
[ Rewrote changelog. ]
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Reviewed-by: Peter Jones <pjones@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: David Herrmann <dh.herrmann@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1462454061-21561-2-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/kernel/sysfb_efi.c | 14 |
1 files changed, 12 insertions, 2 deletions
diff --git a/arch/x86/kernel/sysfb_efi.c b/arch/x86/kernel/sysfb_efi.c index b285d4e8c68e..5da924bbf0a0 100644 --- a/arch/x86/kernel/sysfb_efi.c +++ b/arch/x86/kernel/sysfb_efi.c @@ -106,14 +106,24 @@ static int __init efifb_set_system(const struct dmi_system_id *id) continue; for (i = 0; i < DEVICE_COUNT_RESOURCE; i++) { resource_size_t start, end; + unsigned long flags; + + flags = pci_resource_flags(dev, i); + if (!(flags & IORESOURCE_MEM)) + continue; + + if (flags & IORESOURCE_UNSET) + continue; + + if (pci_resource_len(dev, i) == 0) + continue; start = pci_resource_start(dev, i); - if (start == 0) - break; end = pci_resource_end(dev, i); if (screen_info.lfb_base >= start && screen_info.lfb_base < end) { found_bar = 1; + break; } } } |