x86: Introduce a new option --reuse-video-type

After commit 060eee58 "x86: use old screen_info if needed", kexec-tools
will force use old screen_info and vga type if failed to determine
current vga type. But it is not always a good idea.

Currently kernel hanging is inspected on some hyper-v VMs after this
commit, because hyperv_fb will mimic EFI (or VESA) VGA on first boot
up, but after the real driver is loaded, it will switch to new mode
and no longer compatible with EFI/VESA VGA. Keep setting
orig_video_isVGA to EFI/VESA VGA flag will get wrong driver loaded and
try to manipulate the framebuffer in a wrong way.

We can't ensure this won't happen on other framebuffer drivers, But
it's a helpful feature if the framebuffer drivers just work. So this
patch introduce a --reuse-video-type options to let user decide if the
old screen_info hould be used unconditional or not.

Signed-off-by: Kairui Song <kasong@redhat.com>
Reviewed-by: Dave Young <dyoung@redhat.com>
Signed-off-by: Simon Horman <horms@verge.net.au>

1 files changed, 1 insertions, 0 deletions

diff --git a/kexec/arch/i386/kexec-x86.h b/kexec/arch/i386/kexec-x86.h
index 51855f8..c2bcd37 100644
--- a/kexec/arch/i386/kexec-x86.h
+++ b/kexec/arch/i386/kexec-x86.h
@@ -52,6 +52,7 @@ struct arch_options_t {
 	enum coretype	core_header_type;
 	uint8_t  	pass_memmap_cmdline;
 	uint8_t		noefi;
+	uint8_t		reuse_video_type;
 };
 
 int multiboot_x86_probe(const char *buf, off_t len);