Re: [Intel-gfx] [PATCH v4 02/31] drm/i915: Don't register backlight when another backlight should be used

Jani Nikula
2022-08-24T12:51:35Z

On Wed, 24 Aug 2022, Hans de Goede <hdegoede@redhat.com> wrote:
> 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.
>
> 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..a4dd7924e0c1 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("Skipping intel_backlight registration\n");

Could use drm_info with drm_device.

Either way,

Reviewed-by: Jani Nikula <jani.nikula@intel.com>

and ack for merging via whichever tree suits you best.

> + return 0;
> + }
> +
> memset(&props, 0, sizeof(props));
> props.type = BACKLIGHT_RAW;

--
Jani Nikula, Intel Open Source Graphics Center