Re: [PATCH 1/2] drm/i915/backlight: Make try_vesa_interface as true

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 2/19/2026 7:54 AM, Suraj Kandpal wrote:
> Make try_vesa_interface as true by default. This is so that there
> is a fallback mechanism for Panels which needs VESA DPCD AUX backlight
> mechanism to work but has a broken VBT indicating otherwise.
>
> Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/15679
> Signed-off-by: Suraj Kandpal <suraj.kandpal@intel.com>
> ---
>   drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> index eb05ef4bd9f6..f14abc48a2a7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux_backlight.c
> @@ -644,7 +644,7 @@ int intel_dp_aux_init_backlight_funcs(struct intel_connector *connector)
>   	struct intel_dp *intel_dp = intel_attached_dp(connector);
>   	struct drm_device *dev = connector->base.dev;
>   	struct intel_panel *panel = &connector->panel;
> -	bool try_intel_interface = false, try_vesa_interface = false;
> +	bool try_intel_interface = false, try_vesa_interface = true;


hmm If we want to fallback to VESA interface and we already check for 
Intel interface first, then I think we can drop the try_vesa_interface 
variable altogether.

In the note below, where the rationale of checking for Intel interface 
is mentioned, there we need to add that some VBTs might be broken (in 
the sense that they advertise Intel interface support, but are missing 
the necessary support in the panel).

In such a case try VESA interface as a fallback.


Regards,

Ankit

>   
>   	/* Check the VBT and user's module parameters to figure out which
>   	 * interfaces to probe