linux-kernel - Re: [PATCH 4/5] efi/libstub: gop: Add support for reading EDID

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Message-ID: <87qzus8vxl.fsf@ocarina.mail-host-address-is-not-set>
Date: Fri, 24 Oct 2025 11:56:38 +0200
From: Javier Martinez Canillas <javierm@...hat.com>
To: Thomas Zimmermann <tzimmermann@...e.de>, ardb@...nel.org, jonathan@...ek.ca
Cc: linux-efi@...r.kernel.org, dri-devel@...ts.freedesktop.org,
 linux-kernel@...r.kernel.org, Thomas Zimmermann <tzimmermann@...e.de>
Subject: Re: [PATCH 4/5] efi/libstub: gop: Add support for reading EDID

Thomas Zimmermann <tzimmermann@...e.de> writes:

> Add support for EFI_EDID_DISCOVERED_PROTOCOL and EFI_EDID_ACTIVE_PROTOCOL
> as defined in UEFI 2.8, sec 12.9. Define GUIDs and data structures in the
> rsp header files.
>
> In the GOP setup function, read the EDID of the primary GOP device. First
> try EFI_EDID_ACTIVE_PROTOCOL, which supports user-specified EDID data. Or
> else try EFI_EDID_DISCOVERED_PROTOCOL, which returns the display device's
> native EDID. If no EDID could be retrieved, clear the storage.
>
> Rename efi_setup_gop() to efi_setup_graphics() to reflect the changes
> Let callers pass an optional instance of struct edid_data, if they are
> interested.
>
> While screen_info and edid_info come from the same device handle, they
> should be considered indendent data. The former refers to the graphics

independent

> mode, the latter refers to the display device. GOP devices might not
> provide both.
>
> Signed-off-by: Thomas Zimmermann <tzimmermann@...e.de>
> ---

[...]

> +static void setup_edid_info(struct edid_info *edid, u32 gop_size_of_edid, u8 *gop_edid)
> +{
> +	if (!gop_edid || gop_size_of_edid < 128)

Can you define a constant for 128 instead of having a magic number ?

Reviewed-by: Javier Martinez Canillas <javierm@...hat.com>

-- 
Best regards,

Javier Martinez Canillas
Core Platforms
Red Hat