Re: [PATCH 07/12] arch/x86: Declare edid_info in <asm/screen_info.h>

Hi

Am 29.06.23 um 14:35 schrieb Arnd Bergmann:

On Thu, Jun 29, 2023, at 13:45, Thomas Zimmermann wrote:

quoted

The global variable edid_info contains the firmware's EDID information
as an extension to the regular screen_info on x86. Therefore move it to
<asm/screen_info.h>.

Add the Kconfig token ARCH_HAS_EDID_INFO to guard against access on
architectures that don't provide edid_info. Select it on x86.

I'm not sure we need another symbol in addition to
CONFIG_FIRMWARE_EDID. Since all the code behind that
existing symbol is also x86 specific, would it be enough
to just add either 'depends on X86' or 'depends on X86 ||
COMPILE_TEST' there?

FIRMWARE_EDID is a user-selectable feature, while ARCH_HAS_EDID_INFO 
announces an architecture feature. They do different things.

Right now, ARCH_HAS_EDID_INFO only works on the old BIOS-based VESA 
systems. In the future, I want to add support for EDID data from EFI and 
OF as well. It would be stored in edid_info. I assume that the new 
symbol will become useful then.

Before this patchset, I originally wanted to make use of edid_info in 
the simpledrm graphics driver. But I found that the rsp code could use 
some work first. Maybe the patchset are already tailored towards the 
future changes.

Best regards
Thomas

       Arnd

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstrasse 146, 90461 Nuernberg, Germany
GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman
HRB 36809 (AG Nuernberg)