Re: [RFC PATCH 12/40] drm/amd/display: add plane HDR multiplier driver-private property

[Harry Wentland <harry.wentland@amd.com>]

On 5/9/23 16:35, Joshua Ashton wrote:
> FWIW, we technically do use it right now, but it is always set to 1 in S.31.32.
> 
> Before we used shaper + 3D LUT we did use it for scaling SDR content,
> but given we always have a shaper + 3D LUT it made sense for us to
> roll that into there.
> 

Ah, that's good. No problem then.

Harry

> On Tue, 9 May 2023 at 20:00, Harry Wentland <harry.wentland@amd.com> wrote:
>>
>> On 5/9/23 12:54, Joshua Ashton wrote:
>>> We currently do not have a use for this as we settled on per-plane 3D
>>> LUT + Shaper, but we might end up wanting to use in our scRGB stack
>>> someday so I would like to keep it.
>>>
>>
>> uAPI should always have a userspace that uses it. But if we go
>> and put it behind an #ifdef anyways I don't mind taking this
>> if we foresee use for it in the near future. A gamescope experiment
>> showing how this can be used to scale sRGB planes would be great.
>> I assume that's sort of how you intend to use it.
>>
>> Harry
>>
>>> On Tue, 9 May 2023 at 16:37, Melissa Wen <mwen@igalia.com> wrote:
>>>>
>>>> On 05/08, Harry Wentland wrote:
>>>>>
>>>>>
>>>>> On 4/23/23 10:10, Melissa Wen wrote:
>>>>>> From: Joshua Ashton <joshua@froggi.es>
>>>>>>
>>>>>> Multiplier to 'gain' the plane. When PQ is decoded using the fixed func
>>>>>> transfer function to the internal FP16 fb, 1.0 -> 80 nits (on AMD at
>>>>>> least) When sRGB is decoded, 1.0 -> 1.0.  Therefore, 1.0 multiplier = 80
>>>>>> nits for SDR content. So if you want, 203 nits for SDR content, pass in
>>>>>> (203.0 / 80.0).
>>>>>>
>>>>>
>>>>> Is gamescope intending to use this?
>>>>
>>>> I don't think so. Again, I'll double check and drop it accordingly.
>>>>
>>>> Melissa
>>>>
>>>>>
>>>>> Harry
>>>>>
>>>>>> Co-developed-by: Melissa Wen <mwen@igalia.com>
>>>>>> Signed-off-by: Melissa Wen <mwen@igalia.com>
>>>>>> Signed-off-by: Joshua Ashton <joshua@froggi.es>
>>>>>> ---
>>>>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_display.c   |  6 +++++
>>>>>>  drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h      |  4 +++
>>>>>>  .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h | 12 +++++++++
>>>>>>  .../amd/display/amdgpu_dm/amdgpu_dm_plane.c   | 25 ++++++++++++++-----
>>>>>>  4 files changed, 41 insertions(+), 6 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
>>>>>> index 24595906dab1..dd658f162f6f 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_display.c
>>>>>> @@ -1326,6 +1326,12 @@ amdgpu_display_create_color_properties(struct amdgpu_device *adev)
>>>>>>             return -ENOMEM;
>>>>>>     adev->mode_info.plane_degamma_tf_property = prop;
>>>>>>
>>>>>> +   prop = drm_property_create_range(adev_to_drm(adev),
>>>>>> +                                    0, "AMD_PLANE_HDR_MULT", 0, UINT_MAX);
>>>>>> +   if (!prop)
>>>>>> +           return -ENOMEM;
>>>>>> +   adev->mode_info.plane_hdr_mult_property = prop;
>>>>>> +
>>>>>>     return 0;
>>>>>>  }
>>>>>>  #endif
>>>>>> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
>>>>>> index ab9ce6f26c90..65a9d62ffbe4 100644
>>>>>> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
>>>>>> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
>>>>>> @@ -387,6 +387,10 @@ struct amdgpu_mode_info {
>>>>>>      * linearize content with or without LUT.
>>>>>>      */
>>>>>>     struct drm_property *plane_degamma_tf_property;
>>>>>> +   /**
>>>>>> +    * @plane_hdr_mult_property:
>>>>>> +    */
>>>>>> +   struct drm_property *plane_hdr_mult_property;
>>>>>>  #endif
>>>>>>  };
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>>>>>> index 005632c1c9ec..bb7307b9cfd5 100644
>>>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>>>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
>>>>>> @@ -51,6 +51,7 @@
>>>>>>
>>>>>>  #define AMDGPU_DMUB_NOTIFICATION_MAX 5
>>>>>>
>>>>>> +#define AMDGPU_HDR_MULT_DEFAULT (0x100000000LL)
>>>>>>  /*
>>>>>>  #include "include/amdgpu_dal_power_if.h"
>>>>>>  #include "amdgpu_dm_irq.h"
>>>>>> @@ -736,6 +737,17 @@ struct dm_plane_state {
>>>>>>      * linearize.
>>>>>>      */
>>>>>>     enum drm_transfer_function degamma_tf;
>>>>>> +   /**
>>>>>> +    * @hdr_mult:
>>>>>> +    *
>>>>>> +    * Multiplier to 'gain' the plane.  When PQ is decoded using the fixed
>>>>>> +    * func transfer function to the internal FP16 fb, 1.0 -> 80 nits (on
>>>>>> +    * AMD at least). When sRGB is decoded, 1.0 -> 1.0, obviously.
>>>>>> +    * Therefore, 1.0 multiplier = 80 nits for SDR content.  So if you
>>>>>> +    * want, 203 nits for SDR content, pass in (203.0 / 80.0).  Format is
>>>>>> +    * S31.32 sign-magnitude.
>>>>>> +    */
>>>>>> +   __u64 hdr_mult;
>>>>>>  #endif
>>>>>>  };
>>>>>>
>>>>>> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>>>>> index 5b458cc0781c..57169dae8b3d 100644
>>>>>> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>>>>> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_plane.c
>>>>>> @@ -1321,8 +1321,10 @@ static void dm_drm_plane_reset(struct drm_plane *plane)
>>>>>>             __drm_atomic_helper_plane_reset(plane, &amdgpu_state->base);
>>>>>>
>>>>>>  #ifdef CONFIG_STEAM_DECK
>>>>>> -   if (amdgpu_state)
>>>>>> +   if (amdgpu_state) {
>>>>>>             amdgpu_state->degamma_tf = DRM_TRANSFER_FUNCTION_DEFAULT;
>>>>>> +           amdgpu_state->hdr_mult = AMDGPU_HDR_MULT_DEFAULT;
>>>>>> +   }
>>>>>>  #endif
>>>>>>  }
>>>>>>
>>>>>> @@ -1424,11 +1426,11 @@ static void dm_drm_plane_destroy_state(struct drm_plane *plane,
>>>>>>  #ifdef CONFIG_STEAM_DECK
>>>>>>  int
>>>>>>  amdgpu_dm_replace_property_blob_from_id(struct drm_device *dev,
>>>>>> -                                          struct drm_property_blob **blob,
>>>>>> -                                          uint64_t blob_id,
>>>>>> -                                          ssize_t expected_size,
>>>>>> -                                          ssize_t expected_elem_size,
>>>>>> -                                          bool *replaced)
>>>>>> +                                   struct drm_property_blob **blob,
>>>>>> +                                   uint64_t blob_id,
>>>>>> +                                   ssize_t expected_size,
>>>>>> +                                   ssize_t expected_elem_size,
>>>>>> +                                   bool *replaced)
>>>>>>  {
>>>>>>     struct drm_property_blob *new_blob = NULL;
>>>>>>
>>>>>> @@ -1482,6 +1484,10 @@ dm_plane_attach_color_mgmt_properties(struct amdgpu_display_manager *dm,
>>>>>>                                        dm->adev->mode_info.plane_degamma_tf_property,
>>>>>>                                        DRM_TRANSFER_FUNCTION_DEFAULT);
>>>>>>     }
>>>>>> +   /* HDR MULT is always available */
>>>>>> +   drm_object_attach_property(&plane->base,
>>>>>> +                              dm->adev->mode_info.plane_hdr_mult_property,
>>>>>> +                              AMDGPU_HDR_MULT_DEFAULT);
>>>>>>  }
>>>>>>
>>>>>>  static int
>>>>>> @@ -1507,6 +1513,11 @@ dm_atomic_plane_set_property(struct drm_plane *plane,
>>>>>>                     dm_plane_state->degamma_tf = val;
>>>>>>                     dm_plane_state->base.color_mgmt_changed = 1;
>>>>>>             }
>>>>>> +   } else if (property == adev->mode_info.plane_hdr_mult_property) {
>>>>>> +           if (dm_plane_state->hdr_mult != val) {
>>>>>> +                   dm_plane_state->hdr_mult = val;
>>>>>> +                   dm_plane_state->base.color_mgmt_changed = 1;
>>>>>> +           }
>>>>>>     } else {
>>>>>>             drm_dbg_atomic(plane->dev,
>>>>>>                            "[PLANE:%d:%s] unknown property [PROP:%d:%s]]\n",
>>>>>> @@ -1533,6 +1544,8 @@ dm_atomic_plane_get_property(struct drm_plane *plane,
>>>>>>                     dm_plane_state->degamma_lut->base.id : 0;
>>>>>>     } else if (property == adev->mode_info.plane_degamma_tf_property) {
>>>>>>             *val = dm_plane_state->degamma_tf;
>>>>>> +   } else if (property == adev->mode_info.plane_hdr_mult_property) {
>>>>>> +           *val = dm_plane_state->hdr_mult;
>>>>>>     } else {
>>>>>>             return -EINVAL;
>>>>>>     }
>>>>>
>>>>>
>>