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SubjectRe: [PATCH] x86/efi-bgrt: remove the check of the version field
On Tue, 09 Aug, at 01:25:46PM, Icenowy Zheng wrote:
> Some broken firmwares have a wrongly filled version field in BGRT table.
> (See http://wiki.osdev.org/Broken_UEFI_implementations )
>
> As we know, these firmwares can also provide correct BGRT image, although
> the table is wrong.
>
> After removing the check of the version field, the kernel can now extract
> the image correctly, and the information is also correct.
>
> Tested on a Thinkpad E531 (68854UC).
>
> Signed-off-by: Icenowy Zheng <icenowy@aosc.xyz>
> ---
> arch/x86/platform/efi/efi-bgrt.c | 5 -----
> 1 file changed, 5 deletions(-)
>
> diff --git a/arch/x86/platform/efi/efi-bgrt.c b/arch/x86/platform/efi/efi-bgrt.c
> index 6a2f569..f492ea0 100644
> --- a/arch/x86/platform/efi/efi-bgrt.c
> +++ b/arch/x86/platform/efi/efi-bgrt.c
> @@ -47,11 +47,6 @@ void __init efi_bgrt_init(void)
> bgrt_tab->header.length, sizeof(*bgrt_tab));
> return;
> }
> - if (bgrt_tab->version != 1) {
> - pr_notice("Ignoring BGRT: invalid version %u (expected 1)\n",
> - bgrt_tab->version);
> - return;
> - }
> if (bgrt_tab->status & 0xfe) {
> pr_notice("Ignoring BGRT: reserved status bits are non-zero %u\n",
> bgrt_tab->status);

This would be less scary if we checked for known broken and known good
version values instead of removing the check altogether, i.e. 0 and 1.

The whole point of the version field is that it tells us about the
layout of the BGRT table, so it's not exactly a useless check.

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