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

[Harry Wentland]

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@xxxxxxxxxx> wrote:
>>
>> On 05/08, Harry Wentland wrote:
>>>
>>>
>>> On 4/23/23 10:10, Melissa Wen wrote:
>>>> From: Joshua Ashton <joshua@xxxxxxxxx>
>>>>
>>>> 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@xxxxxxxxxx>
>>>> Signed-off-by: Melissa Wen <mwen@xxxxxxxxxx>
>>>> Signed-off-by: Joshua Ashton <joshua@xxxxxxxxx>
>>>> ---
>>>>  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;
>>>>     }
>>>
>>>