efi: Fix the ACPI BGRT driver for images located in EFI boot services memory
The ACPI BGRT driver accesses the BIOS logo image when it initializes.
However, ACPI 5.0 (which introduces the BGRT) recommends putting the
logo image in EFI boot services memory, so that the OS can reclaim that
memory. Production systems follow this recommendation, breaking the
ACPI BGRT driver.
Move the bulk of the BGRT code to run during a new EFI late
initialization phase, which occurs after switching EFI to virtual mode,
and after initializing ACPI, but before freeing boot services memory.
Copy the BIOS logo image to kernel memory at that point, and make it
accessible to the BGRT driver. Rework the existing ACPI BGRT driver to
act as a simple wrapper exposing that image (and the properties from the
BGRT) via sysfs.
Signed-off-by: Josh Triplett <josh@joshtriplett.org>
Link: http://lkml.kernel.org/r/93ce9f823f1c1f3bb88bdd662cce08eee7a17f5d.1348876882.git.josh@joshtriplett.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig
index 8099895..119d58d 100644
--- a/drivers/acpi/Kconfig
+++ b/drivers/acpi/Kconfig
@@ -385,8 +385,8 @@
to override that restriction).
config ACPI_BGRT
- tristate "Boottime Graphics Resource Table support"
- default n
+ bool "Boottime Graphics Resource Table support"
+ depends on EFI
help
This driver adds support for exposing the ACPI Boottime Graphics
Resource Table, which allows the operating system to obtain