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authorMatt Fleming <matt.fleming@intel.com>2013-10-04 12:36:56 +0400
committerMatt Fleming <matt.fleming@intel.com>2013-10-28 22:09:58 +0400
commit72548e836b0c4abbb652e791dee9c91203a9a4c6 (patch)
tree2eead15738f173ed08ecbedc88adbb0bf2937022 /arch/x86/Kconfig.debug
parentc158c3bf59951bbb44bd7ccca9e6665dfd1617c5 (diff)
downloadlinux-72548e836b0c4abbb652e791dee9c91203a9a4c6.tar.xz
x86/efi: Add EFI framebuffer earlyprintk support
It's incredibly difficult to diagnose early EFI boot issues without special hardware because earlyprintk=vga doesn't work on EFI systems. Add support for writing to the EFI framebuffer, via earlyprintk=efi, which will actually give users a chance of providing debug output. Cc: H. Peter Anvin <hpa@zytor.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Peter Jones <pjones@redhat.com> Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Diffstat (limited to 'arch/x86/Kconfig.debug')
-rw-r--r--arch/x86/Kconfig.debug10
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/Kconfig.debug b/arch/x86/Kconfig.debug
index 78d91afb8e50..0f3621ed1db6 100644
--- a/arch/x86/Kconfig.debug
+++ b/arch/x86/Kconfig.debug
@@ -59,6 +59,16 @@ config EARLY_PRINTK_DBGP
with klogd/syslogd or the X server. You should normally N here,
unless you want to debug such a crash. You need usb debug device.
+config EARLY_PRINTK_EFI
+ bool "Early printk via the EFI framebuffer"
+ depends on EFI && EARLY_PRINTK
+ select FONT_SUPPORT
+ ---help---
+ Write kernel log output directly into the EFI framebuffer.
+
+ This is useful for kernel debugging when your machine crashes very
+ early before the console code is initialized.
+
config X86_PTDUMP
bool "Export kernel pagetable layout to userspace via debugfs"
depends on DEBUG_KERNEL