[PATCH] efifb: BGRT: Add check for new BGRT status field rotation bits

[Ard Biesheuvel]

On Wed, 29 May 2019 at 17:46, Hans de Goede <hdegoede at redhat.com> wrote:
>
> Starting with ACPI 6.2 bits 1 and 2 of the BGRT status field are no longer
> reserved. These bits are now used to indicate if the image needs to be
> rotated before being displayed.
>
> The efifb code does not support rotating the image before copying it to
> the screen.
>
> This commit adds a check for these new bits and if they are set leaves the
> fb contents as is instead of trying to use the un-rotated BGRT image.
>
> Signed-off-by: Hans de Goede <hdegoede at redhat.com>

Acked-by: Ard Biesheuvel <ard.biesheuvel at linaro.org>

> ---
>  drivers/video/fbdev/efifb.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/drivers/video/fbdev/efifb.c b/drivers/video/fbdev/efifb.c
> index 9f39f0c360e0..dfa8dd47d19d 100644
> --- a/drivers/video/fbdev/efifb.c
> +++ b/drivers/video/fbdev/efifb.c
> @@ -169,6 +169,11 @@ static void efifb_show_boot_graphics(struct fb_info *info)
>                 return;
>         }
>
> +       if (bgrt_tab.status & 0x06) {
> +               pr_info("efifb: BGRT rotation bits set, not showing boot graphics\n");
> +               return;
> +       }
> +
>         /* Avoid flashing the logo if we're going to print std probe messages */
>         if (console_loglevel > CONSOLE_LOGLEVEL_QUIET)
>                 return;
> --
> 2.21.0
>