Re: [Nouveau] [PATCH v5 02/31] drm/i915: Don't register backlight when another backlight should be used (v2)

[Dmitry Osipenko <digetx@gmail.com>]

25.08.2022 17:36, Hans de Goede пишет:
> Before this commit when we want userspace to use the acpi_video backlight
> device we register both the GPU's native backlight device and acpi_video's
> firmware acpi_video# backlight device. This relies on userspace preferring
> firmware type backlight devices over native ones.
> 
> Registering 2 backlight devices for a single display really is
> undesirable, don't register the GPU's native backlight device when
> another backlight device should be used.
> 
> Changes in v2:
> - Use drm_info(drm_dev,  ...) for log messages
> 
> Reviewed-by: Jani Nikula <jani.nikula@intel.com>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/gpu/drm/i915/display/intel_backlight.c | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
> index 681ebcda97ad..03c7966f68d6 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -8,6 +8,8 @@
>  #include <linux/pwm.h>
>  #include <linux/string_helpers.h>
>  
> +#include <acpi/video.h>
> +
>  #include "intel_backlight.h"
>  #include "intel_backlight_regs.h"
>  #include "intel_connector.h"
> @@ -952,6 +954,11 @@ int intel_backlight_device_register(struct intel_connector *connector)
>  
>  	WARN_ON(panel->backlight.max == 0);
>  
> +	if (!acpi_video_backlight_use_native()) {
> +		drm_info(&i915->drm, "Skipping intel_backlight registration\n");
> +		return 0;
> +	}
> +
>  	memset(&props, 0, sizeof(props));
>  	props.type = BACKLIGHT_RAW;
>  

This breaks backlight on Acer Chromebook Spin 713 because backlight
isn't registered anymore. Any ideas how to fix it?