[Freedreno] [PATCH v6 4/4] drm: allow real encoder to be passed for drm_writeback_connector

Abhinav Kumar quic_abhinavk at quicinc.com
Tue Apr 5 16:53:57 UTC 2022


Hi Laurent

On 4/5/2022 9:47 AM, Laurent Pinchart wrote:
> Hi Rob and Abhinav,
> 
> On Mon, Apr 04, 2022 at 11:43:37AM -0700, Rob Clark wrote:
>> On Fri, Apr 1, 2022 at 8:38 AM Laurent Pinchart wrote:
>>> On Thu, Mar 31, 2022 at 05:12:13PM -0700, Abhinav Kumar wrote:
>>>> For some vendor driver implementations, display hardware can
>>>> be shared between the encoder used for writeback and the physical
>>>> display.
>>>>
>>>> In addition resources such as clocks and interrupts can
>>>> also be shared between writeback and the real encoder.
>>>>
>>>> To accommodate such vendor drivers and hardware, allow
>>>> real encoder to be passed for drm_writeback_connector.
>>>>
>>>> changes in v6:
>>>>        - assign the encoder inside
>>>>          drm_writeback_connector_init_with_encoder() for
>>>>          better readability
>>>>        - improve some documentation for internal encoder
>>>>
>>>> Co-developed-by: Kandpal Suraj <suraj.kandpal at intel.com>
>>>> Signed-off-by: Kandpal Suraj <suraj.kandpal at intel.com>
>>>> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
>>>> ---
>>>>   drivers/gpu/drm/drm_writeback.c | 18 ++++++++++++------
>>>>   drivers/gpu/drm/vc4/vc4_txp.c   | 14 ++++++++------
>>>>   include/drm/drm_writeback.h     | 21 +++++++++++++++++++--
>>>
>>> Please split this in two patches, one for the DRM core and one for the
>>> VC4 driver. This applies to most patches as a general rule, with the
>>> main exception being API refactoring that requires changing the
>>> implementation and all its users in a single patch.
>>
>> But this *is* API refactoring ;-)
> 
> Partly at least :-) Looking at the API change itself, wouldn't we
> minimize the extra changes to vc4 if we moved this patch before 3/4 ?

I can move all the changes done in vc4 except below part to the change 
3/4 itself because that way I can show usage of vc4->drm_enc with the 
new API. Let me know if that works.

The only part which will remain is the below one:

@@ -523,7 +525,7 @@  static int vc4_txp_bind(struct device *dev, struct 
device *master, void *data)
  	if (ret)
  		return ret;

-	encoder = &txp->connector.encoder;
+	encoder = txp->connector.encoder;
  	encoder->possible_crtcs = drm_crtc_mask(crtc);

Since i dont know vc4 driver very well, I was not sure of a good way to 
decouple this dependency.

Let me know if that works.

Thanks

Abhinav

> 
>>>>   3 files changed, 39 insertions(+), 14 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
>>>> index 797223c..7f72109 100644
>>>> --- a/drivers/gpu/drm/drm_writeback.c
>>>> +++ b/drivers/gpu/drm/drm_writeback.c
>>>> @@ -179,21 +179,21 @@ int drm_writeback_connector_init(struct drm_device *dev,
>>>>   {
>>>>        int ret = 0;
>>>>
>>>> -     drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
>>>> +     drm_encoder_helper_add(&wb_connector->internal_encoder, enc_helper_funcs);
>>>>
>>>> -     wb_connector->encoder.possible_crtcs = possible_crtcs;
>>>> +     wb_connector->internal_encoder.possible_crtcs = possible_crtcs;
>>>>
>>>> -     ret = drm_encoder_init(dev, &wb_connector->encoder,
>>>> +     ret = drm_encoder_init(dev, &wb_connector->internal_encoder,
>>>>                               &drm_writeback_encoder_funcs,
>>>>                               DRM_MODE_ENCODER_VIRTUAL, NULL);
>>>>        if (ret)
>>>>                return ret;
>>>>
>>>> -     ret = drm_writeback_connector_init_with_encoder(dev, wb_connector, &wb_connector->encoder,
>>>> -                     con_funcs, formats, n_formats);
>>>> +     ret = drm_writeback_connector_init_with_encoder(dev, wb_connector,
>>>> +                     &wb_connector->internal_encoder, con_funcs, formats, n_formats);
>>>>
>>>>        if (ret)
>>>> -             drm_encoder_cleanup(&wb_connector->encoder);
>>>> +             drm_encoder_cleanup(&wb_connector->internal_encoder);
>>>>
>>>>        return ret;
>>>>   }
>>>> @@ -238,6 +238,12 @@ int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
>>>>        struct drm_mode_config *config = &dev->mode_config;
>>>>        int ret = create_writeback_properties(dev);
>>>>
>>>> +     /*
>>>> +      * Assign the encoder passed to this API to the wb_connector's encoder.
>>>> +      * For drm_writeback_connector_init(), this shall be the internal_encoder
>>>> +      */
>>>> +     wb_connector->encoder = enc;
>>>> +
>>>>        if (ret != 0)
>>>>                return ret;
>>>>
>>>> diff --git a/drivers/gpu/drm/vc4/vc4_txp.c b/drivers/gpu/drm/vc4/vc4_txp.c
>>>> index 5e53f02..a9b4f83 100644
>>>> --- a/drivers/gpu/drm/vc4/vc4_txp.c
>>>> +++ b/drivers/gpu/drm/vc4/vc4_txp.c
>>>> @@ -151,6 +151,8 @@ struct vc4_txp {
>>>>
>>>>        struct platform_device *pdev;
>>>>
>>>> +     struct drm_encoder drm_enc;
>>>> +
>>>>        struct drm_writeback_connector connector;
>>>>
>>>>        void __iomem *regs;
>>>> @@ -159,7 +161,7 @@ struct vc4_txp {
>>>>
>>>>   static inline struct vc4_txp *encoder_to_vc4_txp(struct drm_encoder *encoder)
>>>>   {
>>>> -     return container_of(encoder, struct vc4_txp, connector.encoder);
>>>> +     return container_of(encoder, struct vc4_txp, drm_enc);
>>>>   }
>>>>
>>>>   static inline struct vc4_txp *connector_to_vc4_txp(struct drm_connector *conn)
>>>> @@ -499,9 +501,9 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>>>>
>>>>        wb_conn = &txp->connector;
>>>>
>>>> -     drm_encoder_helper_add(&wb_conn->encoder, &vc4_txp_encoder_helper_funcs);
>>>> +     drm_encoder_helper_add(&txp->drm_enc, &vc4_txp_encoder_helper_funcs);
>>>>
>>>> -     ret = drm_encoder_init(drm, &wb_conn->encoder,
>>>> +     ret = drm_encoder_init(drm, &txp->drm_enc,
>>>>                        &vc4_txp_encoder_funcs,
>>>>                        DRM_MODE_ENCODER_VIRTUAL, NULL);
>>>>
>>>> @@ -511,10 +513,10 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>>>>        drm_connector_helper_add(&wb_conn->base,
>>>>                                 &vc4_txp_connector_helper_funcs);
>>>>
>>>> -     ret = drm_writeback_connector_init_with_encoder(drm, wb_conn, &wb_conn->encoder,
>>>> +     ret = drm_writeback_connector_init_with_encoder(drm, wb_conn, &txp->drm_enc,
>>>>                        &vc4_txp_connector_funcs, drm_fmts, ARRAY_SIZE(drm_fmts));
>>>>        if (ret) {
>>>> -             drm_encoder_cleanup(&wb_conn->encoder);
>>>> +             drm_encoder_cleanup(&txp->drm_enc);
>>>>                return ret;
>>>>        }
>>>>
>>>> @@ -523,7 +525,7 @@ static int vc4_txp_bind(struct device *dev, struct device *master, void *data)
>>>>        if (ret)
>>>>                return ret;
>>>>
>>>> -     encoder = &txp->connector.encoder;
>>>> +     encoder = txp->connector.encoder;
>>>>        encoder->possible_crtcs = drm_crtc_mask(crtc);
>>>>
>>>>        ret = devm_request_irq(dev, irq, vc4_txp_interrupt, 0,
>>>> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
>>>> index 4795024..3f5c330 100644
>>>> --- a/include/drm/drm_writeback.h
>>>> +++ b/include/drm/drm_writeback.h
>>>> @@ -25,15 +25,32 @@ struct drm_writeback_connector {
>>>>        struct drm_connector base;
>>>>
>>>>        /**
>>>> -      * @encoder: Internal encoder used by the connector to fulfill
>>>> +      * @encoder: handle to drm_encoder used by the connector to fulfill
>>>>         * the DRM framework requirements. The users of the
>>>>         * @drm_writeback_connector control the behaviour of the @encoder
>>>>         * by passing the @enc_funcs parameter to drm_writeback_connector_init()
>>>>         * function.
>>>> +      *
>>>> +      * For some vendor drivers, the hardware resources are shared between
>>>> +      * writeback encoder and rest of the display pipeline.
>>>> +      * To accommodate such cases, encoder is a handle to the real encoder
>>>> +      * hardware.
>>>> +      *
>>>> +      * For current existing writeback users, this shall continue to be the
>>>> +      * embedded encoder for the writeback connector.
>>>>         */
>>>> -     struct drm_encoder encoder;
>>>> +     struct drm_encoder *encoder;
>>>>
>>>>        /**
>>>> +      * @internal_encoder: internal encoder used by writeback when
>>>> +      * drm_writeback_connector_init() is used.
>>>> +      * @encoder will be assigned to this for those cases
>>>> +      *
>>>> +      * This will be unused when drm_writeback_connector_init_with_encoder()
>>>> +      * is used.
>>>> +      */
>>>> +     struct drm_encoder internal_encoder;
>>>> +     /**
>>>>         * @pixel_formats_blob_ptr:
>>>>         *
>>>>         * DRM blob property data for the pixel formats list on writeback
> 


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