[Intel-gfx] [PATCH v4 04/31] drm/radeon: Don't register backlight when another backlight should be used (v3)

Hans de Goede
2022-08-24T12:17:07Z

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>
---
drivers/gpu/drm/Kconfig | 7 +++++++
drivers/gpu/drm/radeon/atombios_encoders.c | 7 +++++++
drivers/gpu/drm/radeon/radeon_legacy_encoders.c | 7 +++++++
3 files changed, 21 insertions(+)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 95ca33938b4a..0471505e951d 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -234,6 +234,13 @@ config DRM_RADEON
select HWMON
select BACKLIGHT_CLASS_DEVICE
select INTERVAL_TREE
+ # radeon 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 an ATI Radeon graphics card. There
are both PCI and AGP versions. You don't need to choose this to
diff --git a/drivers/gpu/drm/radeon/atombios_encoders.c b/drivers/gpu/drm/radeon/atombios_encoders.c
index 0eae05dfb385..c841c273222e 100644
--- a/drivers/gpu/drm/radeon/atombios_encoders.c
+++ b/drivers/gpu/drm/radeon/atombios_encoders.c
@@ -32,6 +32,8 @@
#include <drm/drm_file.h>
#include <drm/radeon_drm.h>

+#include <acpi/video.h>
+
#include "atom.h"
#include "radeon_atombios.h"
#include "radeon.h"
@@ -209,6 +211,11 @@ void radeon_atom_backlight_init(struct radeon_encoder *radeon_encoder,
if (!(rdev->mode_info.firmware_flags & ATOM_BIOS_INFO_BL_CONTROLLED_BY_GPU))
return;

+ if (!acpi_video_backlight_use_native()) {
+ drm_info(dev, "Skipping radeon atom DIG backlight registration\n");
+ return;
+ }
+
pdata = kmalloc(sizeof(struct radeon_backlight_privdata), GFP_KERNEL);
if (!pdata) {
DRM_ERROR("Memory allocation failed\n");
diff --git a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
index 1a66fb969ee7..0cd32c65456c 100644
--- a/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
+++ b/drivers/gpu/drm/radeon/radeon_legacy_encoders.c
@@ -33,6 +33,8 @@
#include <drm/drm_util.h>
#include <drm/radeon_drm.h>

+#include <acpi/video.h>
+
#include "radeon.h"
#include "radeon_asic.h"
#include "radeon_legacy_encoders.h"
@@ -387,6 +389,11 @@ void radeon_legacy_backlight_init(struct radeon_encoder *radeon_encoder,
return;
#endif

+ if (!acpi_video_backlight_use_native()) {
+ drm_info(dev, "Skipping radeon legacy LVDS backlight registration\n");
+ return;
+ }
+
pdata = kmalloc(sizeof(struct radeon_backlight_privdata), GFP_KERNEL);
if (!pdata) {
DRM_ERROR("Memory allocation failed\n");
--
2.37.2