[PATCH v5 2/4] drm: introduce drm_writeback_connector_init_with_encoder() API
Liviu Dudau
liviu.dudau at arm.com
Wed Mar 23 16:46:22 UTC 2022
On Mon, Mar 21, 2022 at 04:56:43PM -0700, Abhinav Kumar wrote:
> For vendors drivers which pass an already allocated and
> initialized encoder especially for cases where the encoder
> hardware is shared OR the writeback encoder shares the resources
> with the rest of the display pipeline introduce a new API,
> drm_writeback_connector_init_with_encoder() which expects
> an initialized encoder as a parameter and only sets up the
> writeback connector.
>
> changes in v5:
> - reorder this change to come before in the series
> to avoid incorrect functionality in subsequent changes
> - continue using struct drm_encoder instead of
> struct drm_encoder * and switch it in next change
>
> Signed-off-by: Abhinav Kumar <quic_abhinavk at quicinc.com>
Hi Abhinav,
> ---
> drivers/gpu/drm/drm_writeback.c | 143 ++++++++++++++++++++++++++++------------
> include/drm/drm_writeback.h | 5 ++
> 2 files changed, 106 insertions(+), 42 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index dc2ef12..abe78b9 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -149,37 +149,15 @@ static const struct drm_encoder_funcs drm_writeback_encoder_funcs = {
> .destroy = drm_encoder_cleanup,
> };
>
> -/**
> - * drm_writeback_connector_init - Initialize a writeback connector and its properties
> - * @dev: DRM device
> - * @wb_connector: Writeback connector to initialize
> - * @con_funcs: Connector funcs vtable
> - * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
> - * @formats: Array of supported pixel formats for the writeback engine
> - * @n_formats: Length of the formats array
> - * @possible_crtcs: possible crtcs for the internal writeback encoder
> - *
> - * This function creates the writeback-connector-specific properties if they
> - * have not been already created, initializes the connector as
> - * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
> - * values. It will also create an internal encoder associated with the
> - * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
> - * the encoder helper.
> - *
> - * Drivers should always use this function instead of drm_connector_init() to
> - * set up writeback connectors.
> - *
> - * Returns: 0 on success, or a negative error code
> - */
> -int drm_writeback_connector_init(struct drm_device *dev,
> - struct drm_writeback_connector *wb_connector,
> - const struct drm_connector_funcs *con_funcs,
> - const struct drm_encoder_helper_funcs *enc_helper_funcs,
> - const u32 *formats, int n_formats, uint32_t possible_crtcs)
> +static int drm_writeback_connector_setup(struct drm_device *dev,
> + struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs, const u32 *formats,
> + int n_formats)
> {
> struct drm_property_blob *blob;
> - struct drm_connector *connector = &wb_connector->base;
> struct drm_mode_config *config = &dev->mode_config;
> + struct drm_connector *connector = &wb_connector->base;
> +
Point of this reordering the statements is...?
> int ret = create_writeback_properties(dev);
>
> if (ret != 0)
> @@ -187,18 +165,10 @@ int drm_writeback_connector_init(struct drm_device *dev,
>
> blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
> formats);
> - if (IS_ERR(blob))
> - return PTR_ERR(blob);
> -
> - drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
> -
> - wb_connector->encoder.possible_crtcs = possible_crtcs;
> -
> - ret = drm_encoder_init(dev, &wb_connector->encoder,
> - &drm_writeback_encoder_funcs,
> - DRM_MODE_ENCODER_VIRTUAL, NULL);
> - if (ret)
> - goto fail;
> + if (IS_ERR(blob)) {
> + ret = PTR_ERR(blob);
> + return ret;
> + }
I don't see why you have changed the earlier code to store the result of PTR_ERR into
ret other than to help your debugging. I suggest that you keep the existing code that
returns PTR_ERR(blob) directly and you will have a nicer diff stat as well.
>
> connector->interlace_allowed = 0;
>
> @@ -237,13 +207,102 @@ int drm_writeback_connector_init(struct drm_device *dev,
> attach_fail:
> drm_connector_cleanup(connector);
> connector_fail:
> - drm_encoder_cleanup(&wb_connector->encoder);
> -fail:
> drm_property_blob_put(blob);
> return ret;
> }
> +
> +/**
> + * drm_writeback_connector_init - Initialize a writeback connector and its properties
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @con_funcs: Connector funcs vtable
> + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
> + * @formats: Array of supported pixel formats for the writeback engine
> + * @n_formats: Length of the formats array
> + * @possible_crtcs: possible crtcs for the internal writeback encoder
> + *
> + * This function creates the writeback-connector-specific properties if they
> + * have not been already created, initializes the connector as
> + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
> + * values. It will also create an internal encoder associated with the
> + * drm_writeback_connector and set it to use the @enc_helper_funcs vtable for
> + * the encoder helper.
> + *
> + * Drivers should always use this function instead of drm_connector_init() to
> + * set up writeback connectors.
> + *
> + * Returns: 0 on success, or a negative error code
> + */
> +int drm_writeback_connector_init(struct drm_device *dev,
> + struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs,
> + const struct drm_encoder_helper_funcs *enc_helper_funcs,
> + const u32 *formats, int n_formats, uint32_t possible_crtcs)
> +{
> + int ret = 0;
> +
> + drm_encoder_helper_add(&wb_connector->encoder, enc_helper_funcs);
> +
> + wb_connector->encoder.possible_crtcs = possible_crtcs;
> +
> + ret = drm_encoder_init(dev, &wb_connector->encoder,
> + &drm_writeback_encoder_funcs,
> + DRM_MODE_ENCODER_VIRTUAL, NULL);
> + if (ret)
> + return ret;
> +
> + ret = drm_writeback_connector_setup(dev, wb_connector, con_funcs, formats,
> + n_formats);
> +
> + if (ret)
> + drm_encoder_cleanup(&wb_connector->encoder);
> +
> + return ret;
> +}
> EXPORT_SYMBOL(drm_writeback_connector_init);
>
> +/**
> + * drm_writeback_connector_init_with_encoder - Initialize a writeback connector and its properties
> + * using the encoder which already assigned and initialized
> + *
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @con_funcs: Connector funcs vtable
> + * @enc_helper_funcs: Encoder helper funcs vtable to be used by the internal encoder
> + * @formats: Array of supported pixel formats for the writeback engine
> + * @n_formats: Length of the formats array
> + *
> + * This function creates the writeback-connector-specific properties if they
> + * have not been already created, initializes the connector as
> + * type DRM_MODE_CONNECTOR_WRITEBACK, and correctly initializes the property
> + * values.
> + *
> + * This function assumes that the drm_writebac_connector's encoder has already been
spelling: writeback
> + * created and initialized before invoking this function.
> + *
> + * In addition, this function also assumes that callers of this API will manage
> + * assigning the encoder helper functions, possible_crtcs and any other encoder
> + * specific operation which is otherwise handled by drm_writeback_connector_init().
> + *
> + * Drivers should always use this function instead of drm_connector_init() to
> + * set up writeback connectors.
.... if they want to manage themselves the lifetime of the associated encoder.
We're not trying to replace drm_writeback_connector_init() function here, only to
provide an alternative function to call for special cases.
> + *
> + * Returns: 0 on success, or a negative error code
> + */
> +int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
> + struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs, const u32 *formats,
> + int n_formats)
Where is the encoder parameter? Isn't that the reason why the function is called
`_with_encoder`?
I think there might have been too many version of these patchsets and things are
starting to be confusing. Please revisit the series without rushing and come up with
a plan of action. My understanding of watching this series has been that you're
trying to come up with a function that does *connector* initialisation but skips the
*encoder* initialisation because it might have been already done by the driver. The
idea will be then to have a function `drm_writeback_connector_init_with_encoder()`
that does *all* the work that `drm_writeback_connector_init()` does at the moment minus
the encoder initialisation part. Then `drm_writeback_connector_init()` only
initialises the internal encoder and calls `drm_writeback_connector_init_with_encoder()`.
There is no need to have the `drm_writeback_connector_setup()` function at all.
Best regards,
Liviu
> +{
> + int ret = 0;
> +
> + ret = drm_writeback_connector_setup(dev, wb_connector, con_funcs, formats,
> + n_formats);
> +
> + return ret;
> +}
> +EXPORT_SYMBOL(drm_writeback_connector_init_with_encoder);
> +
> int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> struct drm_framebuffer *fb)
> {
> diff --git a/include/drm/drm_writeback.h b/include/drm/drm_writeback.h
> index db6214f..0093bab 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -152,6 +152,11 @@ int drm_writeback_connector_init(struct drm_device *dev,
> const struct drm_encoder_helper_funcs *enc_helper_funcs,
> const u32 *formats, int n_formats, uint32_t possible_crtcs);
>
> +int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
> + struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs, const u32 *formats,
> + int n_formats);
> +
> int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> struct drm_framebuffer *fb);
>
> --
> 2.7.4
>
--
====================
| I would like to |
| fix the world, |
| but they're not |
| giving me the |
\ source code! /
---------------
¯\_(ツ)_/¯
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