Hey Louis,
> Currently drm_writeback_connector are created by
> drm_writeback_connector_init or drm_writeback_connector_init_with_encoder.
> Both of the function uses drm_connector_init and drm_encoder_init, but
> there is no way to properly clean those structure from outside. By using
> drm managed variants, we can ensure that the writeback connector is
> properly cleaned.
>
> This patch introduce drmm_writeback_connector_init, an helper to initialize
> a writeback connector using drm managed helpers. This function allows the
> caller to use its own encoder.
>
> Signed-off-by: Louis Chauvet <louis.chauvet@xxxxxxxxxxx>
> ---
> Hi Maxime, Jani,
>
> I tried with this commit to implement the drm-managed version of writeback
> connector initialization. I tested with the current vkms driver, and it
> seems to works (at least no crash/warns).
>
> As suggested by Jani, I only created one function, which takes a
> NULL-able pointer for encoder/encoder functions/possible_crtc. What do you
> think about it?
>
> Regarding the documentation, I think I repeated too much, can I simply add
> comments like "see documentation of @... for the details / requirements"?
>
> Good weekend,
> Louis Chauvet
> ---
> drivers/gpu/drm/drm_writeback.c | 224 ++++++++++++++++++++++++++++++++++------
> include/drm/drm_writeback.h | 7 ++
> 2 files changed, 201 insertions(+), 30 deletions(-)
>
>
> ---
> base-commit: a6bb1f77a94335de67dba12e7f52651c115b82d2
> change-id: 20240829-writeback-drmm-b9b85dcdaf7b
>
> Best regards,
>
> diff --git a/drivers/gpu/drm/drm_writeback.c b/drivers/gpu/drm/drm_writeback.c
> index a031c335bdb9..a161deeea908 100644
> --- a/drivers/gpu/drm/drm_writeback.c
> +++ b/drivers/gpu/drm/drm_writeback.c
> @@ -18,6 +18,7 @@
> #include <drm/drm_modeset_helper_vtables.h>
> #include <drm/drm_property.h>
> #include <drm/drm_writeback.h>
> +#include <drm/drm_managed.h>
Includes are sort alphabetically, you might want to move this one up.
>
> /**
> * DOC: overview
> @@ -202,13 +203,12 @@ int drm_writeback_connector_init(struct drm_device *dev,
> EXPORT_SYMBOL(drm_writeback_connector_init);
>
> /**
> - * drm_writeback_connector_init_with_encoder - Initialize a writeback connector with
> - * a custom encoder
> + * __drm_writeback_connector_init - Common initialization code for writeback
> + * connector
> *
> * @dev: DRM device
> * @wb_connector: Writeback connector to initialize
> * @enc: handle to the already initialized drm encoder
> - * @con_funcs: Connector funcs vtable
> * @formats: Array of supported pixel formats for the writeback engine
> * @n_formats: Length of the formats array
> *
> @@ -224,41 +224,31 @@ EXPORT_SYMBOL(drm_writeback_connector_init);
> * assigning the encoder helper functions, possible_crtcs and any other encoder
> * specific operation.
> *
> - * 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.
> - *
> * 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, struct drm_encoder *enc,
> - const struct drm_connector_funcs *con_funcs, const u32 *formats,
> - int n_formats)
> +static int __drm_writeback_connector_init(
> + struct drm_device *dev, struct drm_writeback_connector *wb_connector,
> + struct drm_encoder *enc, const u32 *formats, int n_formats)
Not a big deal, but ./scripts/checkpatch.pl complains about this
ideantation:
CHECK: Lines should not end with a '('
CHECK: Alignment should match open parenthesis
You can fix it with:
static int __drm_writeback_connector_init(struct drm_device *dev,
struct drm_writeback_connector *wb_connector,
struct drm_encoder *enc,
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;
> - int ret = create_writeback_properties(dev);
> -
> - if (ret != 0)
> - return ret;
> -
> - blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
> - formats);
> - if (IS_ERR(blob))
> - return PTR_ERR(blob);
> -
> + struct drm_property_blob *blob;
> + int ret;
>
> connector->interlace_allowed = 0;
>
> - ret = drm_connector_init(dev, connector, con_funcs,
> - DRM_MODE_CONNECTOR_WRITEBACK);
> + ret = create_writeback_properties(dev);
> if (ret)
> - goto connector_fail;
> + return ret;
>
> ret = drm_connector_attach_encoder(connector, enc);
> if (ret)
> - goto attach_fail;
> + return ret;
> +
> + blob = drm_property_create_blob(dev, n_formats * sizeof(*formats),
> + formats);
> + if (IS_ERR(blob))
> + return PTR_ERR(blob);
>
> INIT_LIST_HEAD(&wb_connector->job_queue);
> spin_lock_init(&wb_connector->job_lock);
> @@ -281,15 +271,189 @@ int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
> wb_connector->pixel_formats_blob_ptr = blob;
>
> return 0;
> +}
> +
> +/**
> + * drm_writeback_connector_init_with_encoder - Initialize a writeback connector with
> + * a custom encoder
> + *
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @enc: handle to the already initialized drm encoder
> + * @con_funcs: Connector funcs vtable
> + * @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_writeback_connector's encoder has already been
> + * 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.
> + *
> + * 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.
> + *
> + * 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, struct drm_encoder *enc,
> + const struct drm_connector_funcs *con_funcs, const u32 *formats,
> + int n_formats)
> +{
> + struct drm_connector *connector = &wb_connector->base;
> + int ret;
> +
> + ret = drm_connector_init(dev, connector, con_funcs,
> + DRM_MODE_CONNECTOR_WRITEBACK);
> + if (ret)
> + return ret;
> +
> + ret = __drm_writeback_connector_init(dev, wb_connector, enc, formats,
> + n_formats);
> + if (ret)
> + drm_connector_cleanup(connector);
>
> -attach_fail:
> - drm_connector_cleanup(connector);
> -connector_fail:
> - drm_property_blob_put(blob);
> return ret;
> }
> EXPORT_SYMBOL(drm_writeback_connector_init_with_encoder);
>
> +/**
> + * drm_writeback_connector_cleanup - Cleanup the writeback connector
> + * @dev: DRM device
> + * @data: Opaque pointer to the writeback connector
> + *
> + * This will decrement the reference counter of blobs and it will clean the
> + * remaining jobs in this writeback connector.
> + */
> +static void drm_writeback_connector_cleanup(struct drm_device *dev, void *data)
> +{
> + struct drm_writeback_connector *wb_connector = data;
> + unsigned long flags;
> + struct drm_writeback_job *pos, *n;
> +
> + drm_property_blob_put(wb_connector->pixel_formats_blob_ptr);
> +
> + spin_lock_irqsave(&wb_connector->job_lock, flags);
> + list_for_each_entry_safe(pos, n, &wb_connector->job_queue, list_entry) {
> + drm_writeback_cleanup_job(pos);
> + list_del(&pos->list_entry);
> + }
> + spin_unlock_irqrestore(&wb_connector->job_lock, flags);
> +}
> +
> +/**
> + * __drmm_writeback_connector_init - Initialize a writeback connector with
> + * a custom encoder
> + *
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @con_funcs: Connector funcs vtable
> + * @enc: handle to the already initialized drm encoder
> + * @formats: Array of supported pixel formats for the writeback engine
> + * @n_formats: Length of the formats array
> + *
> + * This function initialize a writeback connector and register its cleanup.
> + * It uses the common helper @__drm_writeback_connector_init to do the
> + * general initialization.
> + *
> + * This function assumes that @enc has already been 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.
> + *
> + * Returns: 0 on success, or a negative error code
> + */
> +static int __drmm_writeback_connector_init(
> + struct drm_device *dev, struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs, struct drm_encoder *enc,
> + const u32 *formats, int n_formats)
checkpatch warnings here as well.
> +{
> + struct drm_connector *connector = &wb_connector->base;
> + int ret;
> +
> + ret = drmm_connector_init(dev, connector, con_funcs,
> + DRM_MODE_CONNECTOR_WRITEBACK, NULL);
> + if (ret)
> + return ret;
> +
> + ret = __drm_writeback_connector_init(dev, wb_connector, enc, formats,
> + n_formats);
> + if (ret) {
> + drm_writeback_connector_cleanup(dev, &wb_connector);
Is it safe to call drm_writeback_connector_cleanup() without initializing
the job_queue and job_lock?
> + return ret;
> + }
> +
> + ret = drmm_add_action_or_reset(dev, &drm_writeback_connector_cleanup,
> + wb_connector);
> + if (ret)
Missing call to drm_writeback_connector_cleanup()?
> + return ret;
> +
> + return 0;
> +}
> +
> +/**
> + * drmm_writeback_connector_init - Initialize a writeback connector with
> + * a custom encoder
> + *
> + * @dev: DRM device
> + * @wb_connector: Writeback connector to initialize
> + * @con_funcs: Connector funcs vtable
> + * @enc: handle to the already initialized drm encoder, optional
> + * @enc_funcs: Encoder funcs vtable, optional
I think that this is only used if @enc is NULL, it'd be nice to clarify
it like you did with @possible_crtcs.
> + * @formats: Array of supported pixel formats for the writeback engine
> + * @n_formats: Length of the formats array
> + * @possible_crtcs: if @enc is NULL, this will set the possible_crtc for the
> + * newly created encoder
> + *
> + * This function initialize a writeback connector and register its cleanup.
> + *
> + * 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.
> + *
> + * If @enc is NULL, a drm-managed encoder is created and used.
> + * If @enc_funcs is not NULL, this vtable is attached to @enc or this new
> + * encoder.
Isn't it only attached when @enc is NULL?
> + *
> + * Returns: 0 on success, or a negative error code
> + */
> +int drmm_writeback_connector_init(
> + struct drm_device *dev, struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs,
> + struct drm_encoder *enc,
> + const struct drm_encoder_helper_funcs *enc_funcs, const u32 *formats,
> + int n_formats, u32 possible_crtcs)
Same checkpatch issues.
> +{
> + int ret;
> +
> + if (!enc) {
> + ret = drmm_encoder_init(dev, &wb_connector->encoder,
> + NULL, DRM_MODE_ENCODER_VIRTUAL, NULL);
> + if (ret)
> + return ret;
> +
> + enc = &wb_connector->encoder;
This modifies an input function parameter, not sure if it's intended
but undocumented.
> + enc->possible_crtcs |= possible_crtcs;
> + if (enc_funcs)
> + drm_encoder_helper_add(enc, enc_funcs);
> + }
> +
> + return __drmm_writeback_connector_init(dev, wb_connector, con_funcs,
> + &wb_connector->encoder, formats,
> + n_formats);
> +}
> +EXPORT_SYMBOL(drmm_writeback_connector_init);
> +
> 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 17e576c80169..88abfd3d4564 100644
> --- a/include/drm/drm_writeback.h
> +++ b/include/drm/drm_writeback.h
> @@ -161,6 +161,13 @@ int drm_writeback_connector_init_with_encoder(struct drm_device *dev,
> const struct drm_connector_funcs *con_funcs, const u32 *formats,
> int n_formats);
>
> +int drmm_writeback_connector_init(
> + struct drm_device *dev, struct drm_writeback_connector *wb_connector,
> + const struct drm_connector_funcs *con_funcs,
> + struct drm_encoder *enc,
> + const struct drm_encoder_helper_funcs *enc_funcs, const u32 *formats,
> + int n_formats, u32 possible_crtcs);
> +
This indentation make checkpatch happy:
int drmm_writeback_connector_init(struct drm_device *dev,
struct drm_writeback_connector *wb_connector,
const struct drm_connector_funcs *con_funcs,
struct drm_encoder *enc,
const struct drm_encoder_helper_funcs *enc_funcs,
const u32 *formats,
int n_formats,
u32 possible_crtcs);
> int drm_writeback_set_fb(struct drm_connector_state *conn_state,
> struct drm_framebuffer *fb);
>
>
