[PATCH v2 03/29] drm/amdgpu: Don't register backlight when another backlight should be used

[Hans de Goede]

Hi,

On 7/20/22 18:46, Alex Deucher wrote:
> On Wed, Jul 20, 2022 at 12:44 PM Alex Deucher <alexdeucher at gmail.com> wrote:
>>
>> On Tue, Jul 12, 2022 at 3:39 PM Hans de Goede <hdegoede at 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.
>>>
>>> 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 && X86 are enabled.
>>>   When these are not set, ACPI_VIDEO is disabled, ensuring the stubs
>>>   from acpi/video.h will be used.
>>>
>>> Signed-off-by: Hans de Goede <hdegoede at redhat.com>
>>
>> Acked-by: Alex Deucher <alexander.deucher at amd.com>
> 
> Actually, can you use dev_info for the messages below rather than
> DRM_INFO?  That makes it easier to tell which GPU is affected in a
> multi-GPU system.  With that changed,
> Acked-by: Alex Deucher <alexander.deucher at amd.com>

Thank you for the ack. I've changed the DRM_INFO(...) calls with
drm_info(drm_dev, ...) calls for the version 3 of this series
which I'm preparing.

Regards,

Hans


> 
>>
>>> ---
>>>  drivers/gpu/drm/Kconfig                           | 6 ++++++
>>>  drivers/gpu/drm/amd/amdgpu/atombios_encoders.c    | 7 +++++++
>>>  drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 7 +++++++
>>>  3 files changed, 20 insertions(+)
>>>
>>> diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
>>> index aaa7ad1f0614..d65119860760 100644
>>> --- a/drivers/gpu/drm/Kconfig
>>> +++ b/drivers/gpu/drm/Kconfig
>>> @@ -258,6 +258,12 @@ config DRM_AMDGPU
>>>         select HWMON
>>>         select BACKLIGHT_CLASS_DEVICE
>>>         select INTERVAL_TREE
>>> +       # amdgpu depends on ACPI_VIDEO when X86 and ACPI are both enabled
>>> +       # for select to work, ACPI_VIDEO's dependencies must also be selected
>>> +       select INPUT if ACPI && X86
>>> +       select X86_PLATFORM_DEVICES if ACPI && X86
>>> +       select ACPI_WMI if ACPI && X86
>>> +       select ACPI_VIDEO 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 fa7421afb9a6..abf209e36fca 100644
>>> --- 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("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 5eb111d35793..3b03a95e59a8 100644
>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
>>> @@ -86,6 +86,8 @@
>>>  #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"
>>> @@ -4050,6 +4052,11 @@ 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("Skipping amdgpu DM backlight registration\n");
>>> +               return;
>>> +       }
>>> +
>>>         props.max_brightness = AMDGPU_MAX_BL_LEVEL;
>>>         props.brightness = AMDGPU_MAX_BL_LEVEL;
>>>         props.type = BACKLIGHT_RAW;
>>> --
>>> 2.36.0
>>>
>