Re: [PATCH] drm/i915: Mark dependency on CONFIG_X86_PAT

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Dec 16, 2025 at 01:35:12PM +0200, Joonas Lahtinen wrote:
> Building the driver without CONFIG_X86_PAT would yield in reduced
> platform/uAPI support and is not currently planned to be supported.
> 
> Add a dependency in Kconfig to avoid issues with such build until
> somebody steps up to fix and validate such builds.

The driver works just fine w/o PAT on older GPUs at least. Otherwise
it wouldn't work at all on any P3 class CPU as the kernel completely
disables PAT support on those even if the kernel is built with
X86_PAT=y. You can also disable PAT on the command line with "nopat".

> 
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15410
> Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Reported-by: Norbert Lange <nolange79@gmail.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Tvrtko Ursulin <tursulin@ursulin.net>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/Kconfig | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/Kconfig b/drivers/gpu/drm/i915/Kconfig
> index 5e939004b6463..a19a233239056 100644
> --- a/drivers/gpu/drm/i915/Kconfig
> +++ b/drivers/gpu/drm/i915/Kconfig
> @@ -2,7 +2,7 @@
>  config DRM_I915
>  	tristate "Intel 8xx/9xx/G3x/G4x/HD Graphics"
>  	depends on DRM
> -	depends on X86 && PCI
> +	depends on X86 && X86_PAT && PCI
>  	depends on !PREEMPT_RT
>  	select INTEL_GTT if X86
>  	select INTERVAL_TREE
> -- 
> 2.52.0

-- 
Ville Syrjälä
Intel