On Wed, 3 Dec 2025 at 10:07, Tvrtko Ursulin <[email protected]> wrote:
>
> Valve Steam Deck has a 800x1280 portrait screen installed in a landscape
> orientation. The firmware offers a software rotated 1280x800 mode which
> GRUB can be made to switch to when displaying a boot menu. If this mode
> was selected frame buffer drivers will see this fake mode and fbcon
> rendering will be corrupted.
>
> Lets therefore add a selective quirk inside the current "swap with and
> height" handling, which will detect this exact mode and fix it up back to
> the native one.
>
> This will allow the DRM based frame buffer drivers to detect the correct
> mode and, apply the existing panel orientation quirk, and render the
> console in landscape mode with no corruption.
>
> Signed-off-by: Tvrtko Ursulin <[email protected]>
> Cc: Thomas Zimmermann <[email protected]>
> Cc: Ard Biesheuvel <[email protected]>
> Cc: Melissa Wen <[email protected]>
> Cc: [email protected]
> ---
> drivers/firmware/efi/sysfb_efi.c | 56 +++++++++++++++++++++++++++++---
> 1 file changed, 51 insertions(+), 5 deletions(-)
>
Thanks for respinning this. But seeing the result, I think we can
simplify this substantially by using two separate callbacks for the
two cases.
> diff --git a/drivers/firmware/efi/sysfb_efi.c
> b/drivers/firmware/efi/sysfb_efi.c
> index eacf9a50eab2..566492e67798 100644
> --- a/drivers/firmware/efi/sysfb_efi.c
> +++ b/drivers/firmware/efi/sysfb_efi.c
> @@ -231,16 +231,42 @@ static const struct dmi_system_id
> efifb_dmi_system_table[] __initconst = {
> {},
> };
>
> +struct efifb_mode_fixup {
> + unsigned int width;
> + unsigned int height;
> + unsigned int linelength;
> +};
> +
> static int __init efifb_swap_width_height(const struct dmi_system_id *id)
> {
Leave this one alone, and add
static int __init efifb_check_and_swap_width_height(const struct
dmi_system_id *id)
{
const struct efifb_mode_fixup *data = id->driver_data;
if (data->width == screen_info.lfb_width &&
data->height == screen_info.lfb_height) {
swap(screen_info.lfb_width, screen_info.lfb_height);
screen_info.lfb_linelength = data->linelength;
screen_info.lfb_size = data->linelength * data->width;
}
return 1;
}
Note that we should always return 1 here, given that there is no point
in trying other matches, even if the width/height check fails.
And please make efifb_steamdeck_mode_fixup __initconst as well
