p71924506
/
linux_old1
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

x86/efi/bgrt: Don't ignore the BGRT if the 'valid' bit is 0 

Unintuitively, the BGRT graphic is apparently meant to be usable
if the valid bit in not set. The valid bit only conveys
uncertainty about the validity in relation to the screen state.

Windows 10 actually uses the BGRT image for its boot screen even
if not 'valid', for example when the user triggered the boot
menu. Because it is unclear if all firmwares will provide a
usable graphic in this case, we now look at the BMP magic number
as an additional check.

Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Môshe van der Sterre <me@moshe.nl>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: =?UTF-8?q?M=C3=B4she=20van=20der=20Sterre?= <me@moshe.nl>
Link: http://lkml.kernel.org/r/1454364428-494-10-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Môshe van der Sterre 2016-02-01 22:07:03 +00:00 committed by Ingo Molnar
parent 9c09a342eb
commit 66dbe99cfe
1 changed files with 5 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

10
arch/x86/platform/efi/efi-bgrt.c
View File

@ -57,11 +57,6 @@ void __init efi_bgrt_init(void)
bgrt_tab->status);
return;
}
if (bgrt_tab->status != 1) {
pr_debug("Ignoring BGRT: invalid status %u (expected 1)\n",
bgrt_tab->status);
return;
}
if (bgrt_tab->image_type != 0) {
pr_err("Ignoring BGRT: invalid image type %u (expected 0)\n",
bgrt_tab->image_type);
@ -80,6 +75,11 @@ void __init efi_bgrt_init(void)
memcpy(&bmp_header, image, sizeof(bmp_header));
memunmap(image);
if (bmp_header.id != 0x4d42) {
pr_err("Ignoring BGRT: Incorrect BMP magic number 0x%x (expected 0x4d42)\n",
bmp_header.id);
return;
}
bgrt_image_size = bmp_header.size;
bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);