drm/amdgpu: Don't register backlight when another backlight should be used (v3)

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:
- To avoid linker errors when amdgpu is builtin and video_detect.c is in
  a module, select ACPI_VIDEO and its deps if ACPI is enabled.
  When ACPI is disabled, ACPI_VIDEO is also always disabled, ensuring
  the stubs from acpi/video.h will be used.

Changes in v3:
- Use drm_info(drm_dev, "...") to log messages
- ACPI_VIDEO can now be enabled on non X86 too,
  adjust the Kconfig changes to match this.

Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 6c2256e..a9139c6 100644 (file)
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -273,6 +273,13 @@ config DRM_AMDGPU
        select BACKLIGHT_CLASS_DEVICE
        select INTERVAL_TREE
        select DRM_BUDDY
+       # amdgpu depends on ACPI_VIDEO when ACPI is enabled, for select to work
+       # ACPI_VIDEO's dependencies must also be selected.
+       select INPUT if ACPI
+       select ACPI_VIDEO if ACPI
+       # On x86 ACPI_VIDEO also needs ACPI_WMI
+       select X86_PLATFORM_DEVICES if ACPI && X86
+       select ACPI_WMI if ACPI && X86
        help
          Choose this option if you have a recent AMD Radeon graphics card.
 

diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
index fa7421a..b4e3ced 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_encoders.c
@@ -26,6 +26,8 @@
 
 #include <linux/pci.h>
 
+#include <acpi/video.h>
+
 #include <drm/drm_crtc_helper.h>
 #include <drm/amdgpu_drm.h>
 #include "amdgpu.h"
@@ -184,6 +186,11 @@ void amdgpu_atombios_encoder_init_backlight(struct amdgpu_encoder *amdgpu_encode
        if (!(adev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU))
                return;
 
+       if (!acpi_video_backlight_use_native()) {
+               drm_info(dev, "Skipping amdgpu atom DIG backlight registration\n");
+               return;
+       }
+
        pdata = kmalloc(sizeof(struct amdgpu_backlight_privdata), GFP_KERNEL);
        if (!pdata) {
                DRM_ERROR("Memory allocation failed\n");

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 8660d93..a64baff 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -89,6 +89,8 @@
 #include <drm/drm_audio_component.h>
 #include <drm/drm_gem_atomic_helper.h>
 
+#include <acpi/video.h>
+
 #include "ivsrcid/dcn/irqsrcs_dcn_1_0.h"
 
 #include "dcn/dcn_1_0_offset.h"
@@ -4055,6 +4057,11 @@ amdgpu_dm_register_backlight_device(struct amdgpu_display_manager *dm)
        amdgpu_dm_update_backlight_caps(dm, dm->num_of_edps);
        dm->brightness[dm->num_of_edps] = AMDGPU_MAX_BL_LEVEL;
 
+       if (!acpi_video_backlight_use_native()) {
+               drm_info(adev_to_drm(dm->adev), "Skipping amdgpu DM backlight registration\n");
+               return;
+       }
+
        props.max_brightness = AMDGPU_MAX_BL_LEVEL;
        props.brightness = AMDGPU_MAX_BL_LEVEL;
        props.type = BACKLIGHT_RAW;