Re: [PATCH 1/1] efi/gop: require shadow if PixelBltOnly

[Glenn Washburn]

On Mon, 28 Aug 2023 23:50:09 +0200
Heinrich Schuchardt <heinrich.schuchardt@canonical.com> wrote:

> If the EFI graphics pixel format is PixelBltOnly, we cannot write directly
> to the frame buffer. We need the shadow frame buffer which we copy via
> the BitBlt operation to the hardware.
> 
> If the pixel format is PixelBltOnly and allocation of the shadow frame
> buffer fails, we must raise an error to signal that the EFI GOP protocol is
> not usable.
> 
> Signed-off-by: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
> ---
>  grub-core/video/efi_gop.c | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/grub-core/video/efi_gop.c b/grub-core/video/efi_gop.c
> index 7247aeea7..09ee71b45 100644
> --- a/grub-core/video/efi_gop.c
> +++ b/grub-core/video/efi_gop.c
> @@ -480,6 +480,10 @@ grub_video_gop_setup (unsigned int width, unsigned int 
> height,
>    if (!buffer)
>      {
>        grub_dprintf ("video", "GOP: couldn't allocate shadow\n");
> +      if (info->pixel_format == GRUB_EFI_GOT_BLT_ONLY)
> +        {
> +          return grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("out of memory"));
> +        }

Trivial nit. Shouldn't these unnecessary braces be removed?

Glenn

>        grub_errno = 0;
>        grub_video_gop_fill_mode_info (gop->mode->mode, info,
>                                    &framebuffer.mode_info);