Hi Laurent,
On Sat, Dec 05, 2020 at 12:01:35AM +0200, Laurent Pinchart wrote:
> devm_kzalloc() is the wrong API to allocate encoders, as the lifetime of
> the encoders is tied to the DRM device, not the device to driver
> binding. drmm_kzalloc() isn't a good option either, as it would result
> in the encoder being freed before being unregistered during the managed
> cleanup of the DRM objects. Use a plain kzalloc(), and register a drmm
> action to cleanup the encoder.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/rcar-du/rcar_du_encoder.c | 47 ++++++++++++++---------
> 1 file changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> index 0edce24f2053..7c491ff72cd2 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
> @@ -8,12 +8,13 @@
> */
>
> #include <linux/export.h>
> +#include <linux/slab.h>
>
> #include <drm/drm_bridge.h>
> #include <drm/drm_crtc.h>
> +#include <drm/drm_managed.h>
> #include <drm/drm_modeset_helper_vtables.h>
> #include <drm/drm_panel.h>
> -#include <drm/drm_simple_kms_helper.h>
>
> #include "rcar_du_drv.h"
> #include "rcar_du_encoder.h"
> @@ -44,6 +45,17 @@ static unsigned int rcar_du_encoder_count_ports(struct device_node *node)
> return num_ports;
> }
>
> +static const struct drm_encoder_funcs rcar_du_encoder_funcs = {
> +};
> +
> +static void rcar_du_encoder_release(struct drm_device *dev, void *res)
> +{
> + struct rcar_du_encoder *renc = res;
> +
> + drm_encoder_cleanup(&renc->base);
> + kfree(renc);
> +}
> +
> int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> enum rcar_du_output output,
> struct device_node *enc_node)
> @@ -53,7 +65,7 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> struct drm_bridge *bridge;
> int ret;
>
> - renc = devm_kzalloc(rcdu->dev, sizeof(*renc), GFP_KERNEL);
> + renc = kzalloc(sizeof(*renc), GFP_KERNEL);
> if (renc == NULL)
> return -ENOMEM;
>
> @@ -76,20 +88,20 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
>
> if (IS_ERR(panel)) {
> ret = PTR_ERR(panel);
> - goto done;
> + goto error;
> }
>
> bridge = devm_drm_panel_bridge_add_typed(rcdu->dev, panel,
> DRM_MODE_CONNECTOR_DPI);
> if (IS_ERR(bridge)) {
> ret = PTR_ERR(bridge);
> - goto done;
> + goto error;
> }
> } else {
> bridge = of_drm_find_bridge(enc_node);
> if (!bridge) {
> ret = -EPROBE_DEFER;
> - goto done;
> + goto error;
> }
>
> if (output == RCAR_DU_OUTPUT_LVDS0 ||
> @@ -104,28 +116,27 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
> if (rcdu->info->gen >= 3 && output == RCAR_DU_OUTPUT_LVDS1) {
> if (rcar_lvds_dual_link(bridge)) {
> ret = -ENOLINK;
> - goto done;
> + goto error;
> }
> }
>
> - ret = drm_simple_encoder_init(rcdu->ddev, encoder,
> - DRM_MODE_ENCODER_NONE);
> + ret = drm_encoder_init(rcdu->ddev, encoder, &rcar_du_encoder_funcs,
> + DRM_MODE_ENCODER_NONE, NULL);
I might have missed the reason for this.
Why add an action later instead of making rcar_du_encoder_release part
of rcar_du_encoder_funcs ?
Thanks
j
> if (ret < 0)
> - goto done;
> + goto error;
> +
> + ret = drmm_add_action_or_reset(rcdu->ddev, rcar_du_encoder_release,
> + renc);
> + if (ret)
> + return ret;
>
> /*
> * Attach the bridge to the encoder. The bridge will create the
> * connector.
> */
> - ret = drm_bridge_attach(encoder, bridge, NULL, 0);
> - if (ret) {
> - drm_encoder_cleanup(encoder);
> - return ret;
> - }
> -
> -done:
> - if (ret < 0)
> - devm_kfree(rcdu->dev, renc);
> + return drm_bridge_attach(encoder, bridge, NULL, 0);
>
> +error:
> + kfree(renc);
> return ret;
> }
> --
> Regards,
>
> Laurent Pinchart
>
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