[PATCH 1/3] drm: Introduce scaling filter mode property

[Sharma, Shashank]

Hello Mihail,

Thanks for your review, my comments inline.

On 10/22/2019 6:56 PM, Mihail Atanassov wrote:
> Hi Shashank,
>
> On Tuesday, 22 October 2019 10:59:44 BST Shashank Sharma wrote:
>> This patch adds a scaling filter mode porperty
>> to allow:
>> - A driver/HW to showcase it's scaling filter capabilities.
>> - A userspace to pick a desired effect while scaling.
>>
>> This option will be particularly useful in the scenarios where
>> Integer mode scaling is possible, and a UI client wants to pick
>> filters like Nearest-neighbor applied for non-blurry outputs.
>>
>> There was a RFC patch series published, to discus the request to enable
>> Integer mode scaling by some of the gaming communities, which can be
>> found here:
>> https://patchwork.freedesktop.org/series/66175/
>>
>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>> ---
>>   drivers/gpu/drm/drm_atomic_uapi.c |  4 ++++
>>   include/drm/drm_crtc.h            | 26 ++++++++++++++++++++++++++
>>   include/drm/drm_mode_config.h     |  6 ++++++
>>   3 files changed, 36 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c
>> index 0d466d3b0809..883329453a86 100644
>> --- a/drivers/gpu/drm/drm_atomic_uapi.c
>> +++ b/drivers/gpu/drm/drm_atomic_uapi.c
>> @@ -435,6 +435,8 @@ static int drm_atomic_crtc_set_property(struct drm_crtc *crtc,
>>                return ret;
>>        } else if (property == config->prop_vrr_enabled) {
>>                state->vrr_enabled = val;
>> +     } else if (property == config->scaling_filter_property) {
>> +             state->scaling_filter = val;
>>        } else if (property == config->degamma_lut_property) {
>>                ret = drm_atomic_replace_property_blob_from_id(dev,
>>                                        &state->degamma_lut,
>> @@ -503,6 +505,8 @@ drm_atomic_crtc_get_property(struct drm_crtc *crtc,
>>                *val = (state->gamma_lut) ? state->gamma_lut->base.id : 0;
>>        else if (property == config->prop_out_fence_ptr)
>>                *val = 0;
>> +     else if (property == config->scaling_filter_property)
>> +             *val = state->scaling_filter;
>>        else if (crtc->funcs->atomic_get_property)
>>                return crtc->funcs->atomic_get_property(crtc, state, property, val);
>>        else
>> diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
>> index 5e9b15a0e8c5..94c5509474a8 100644
>> --- a/include/drm/drm_crtc.h
>> +++ b/include/drm/drm_crtc.h
>> @@ -58,6 +58,25 @@ struct device_node;
>>   struct dma_fence;
>>   struct edid;
>>
>> +enum drm_scaling_filters {
>> +     DRM_SCALING_FILTER_DEFAULT,
>> +     DRM_SCALING_FILTER_MEDIUM,
>> +     DRM_SCALING_FILTER_BILINEAR,
>> +     DRM_SCALING_FILTER_NN,
>> +     DRM_SCALING_FILTER_NN_IS_ONLY,
>> +     DRM_SCALING_FILTER_EDGE_ENHANCE,
> This one looks to be missing a stringified version below.
Oh yes, it did. Thanks for pointing this out.
>   Just wanted
> to jump in early and suggest dropping it from the scaling filter enum.
> Edge enhancement is orthogonal to the mode used for scaling, at least
> on komeda HW, so we wouldn't be able to make the best use of the
> property in its current form.
Yes, Ville also suggested similar, I guess we can start with the smaller 
set.
>
>> +     DRM_SCALING_FILTER_INVALID,
>> +};
>> +
>> +static const struct drm_prop_enum_list drm_scaling_filter_enum_list[] = {
>> +     { DRM_SCALING_FILTER_DEFAULT, "Default" },
>> +     { DRM_SCALING_FILTER_MEDIUM, "Medium" },
>> +     { DRM_SCALING_FILTER_BILINEAR, "Bilinear" },
>> +     { DRM_SCALING_FILTER_NN, "Nearest Neighbor" },
>> +     { DRM_SCALING_FILTER_NN_IS_ONLY, "Integer Mode Scaling" },
>> +     { DRM_SCALING_FILTER_INVALID, "Invalid" },
>> +};
>> +
>>   static inline int64_t U642I64(uint64_t val)
>>   {
>>        return (int64_t)*((int64_t *)&val);
>> @@ -283,6 +302,13 @@ struct drm_crtc_state {
>>         */
>>        u32 target_vblank;
>>
>> +     /**
>> +      * @scaling_filter:
>> +      *
>> +      * Scaling filter mode to be applied
>> +      */
>> +     u32 scaling_filter;
>> +
>>        /**
>>         * @async_flip:
>>         *
>> diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h
>> index 3bcbe30339f0..efd6fd55770f 100644
>> --- a/include/drm/drm_mode_config.h
>> +++ b/include/drm/drm_mode_config.h
>> @@ -914,6 +914,12 @@ struct drm_mode_config {
>>         */
>>        struct drm_property *modifiers_property;
>>
>> +     /**
>> +      * @scaling_filter_property: CRTC property to apply a particular filter
> A scaling filter option can also be useful for scaling individual
> planes, do you have any plans to extend the property's applications
> in that direction?

Yes, the second stage of development should contain the plane level 
filtering too, but as you know, that would be a complex thing to handle, 
as planes apply filter pre-blending. We need to discus that (in a 
parallel thread :)) how should that look like.

- Shashank

>
>> +      * while scaling in panel fitter mode.
>> +      */
>> +     struct drm_property *scaling_filter_property;
>> +
>>        /* cursor size */
>>        uint32_t cursor_width, cursor_height;
>>
>>
>
> --
> Mihail
>
>
>
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