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authorWang YanQing <udknight@gmail.com>2016-05-05 14:14:21 +0100
committerSasha Levin <sasha.levin@oracle.com>2016-05-17 13:42:59 -0400
commitade3716f4dff60c9aab9f71a5190615effbdf169 (patch)
treea3354f2eb3633fd05d371206eeaabdeaddbe6734 /arch
parent1669540814a1cf57ff50e037c5bf84f831ea4e09 (diff)
x86/sysfb_efi: Fix valid BAR address range check
[ Upstream commit c10fcb14c7afd6688c7b197a814358fecf244222 ] 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> Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/sysfb_efi.c14
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;
}
}
}