Hi Pratyush, On Wed, Sep 15, 2021 at 05:32:37PM +0530, Pratyush Yadav wrote: ... > +/* > + * Find the input format. This is done by finding the first device in the > + * pipeline which can tell us the current format. This could be the sensor, or > + * this could be another device in the middle which is capable of format > + * conversions. > + */ > +static int ti_csi2rx_validate_pipeline(struct ti_csi2rx_dev *csi) > +{ > + struct media_pipeline *pipe = &csi->pipe; > + struct media_entity *entity; > + struct v4l2_subdev *sd; > + struct v4l2_subdev_format fmt; > + struct v4l2_pix_format *pix = &csi->v_fmt.fmt.pix; > + struct media_device *mdev = &csi->mdev; > + const struct ti_csi2rx_fmt *ti_fmt; > + int ret; > + > + mutex_lock(&mdev->graph_mutex); > + ret = media_graph_walk_init(&pipe->graph, mdev); > + if (ret) { > + mutex_unlock(&mdev->graph_mutex); > + return ret; > + } > + > + media_graph_walk_start(&pipe->graph, &csi->vdev.entity); > + > + while ((entity = media_graph_walk_next(&pipe->graph))) { > + if (!is_media_entity_v4l2_subdev(entity)) > + continue; You shouldn't rely on media_graph_walk_next() to return entities in a particular order. I'd suggest approach taken in isp_video_check_external_subdevs() (in drivers/media/platform/omap3isp/ispvideo.c). > + > + sd = media_entity_to_v4l2_subdev(entity); > + > + fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE; > + fmt.pad = media_get_pad_index(entity, 0, PAD_SIGNAL_DEFAULT); > + > + ret = v4l2_subdev_call(sd, pad, get_fmt, NULL, &fmt); > + if (ret && ret != -ENOIOCTLCMD) { > + media_graph_walk_cleanup(&pipe->graph); > + mutex_unlock(&mdev->graph_mutex); > + return ret; > + } > + > + if (!ret) > + break; > + } > + > + media_graph_walk_cleanup(&pipe->graph); > + mutex_unlock(&mdev->graph_mutex); > + > + /* Could not find input format. */ > + if (!entity) > + return -EPIPE; > + > + if (fmt.format.width != pix->width) > + return -EPIPE; > + if (fmt.format.height != pix->height) > + return -EPIPE; Pipeline validation should take place during media_pipeline_start(). Why are you doing it here? > + > + ti_fmt = find_format_by_pix(pix->pixelformat); > + if (WARN_ON(!ti_fmt)) > + return -EINVAL; > + > + if (fmt.format.code == MEDIA_BUS_FMT_YUYV8_2X8 || > + fmt.format.code == MEDIA_BUS_FMT_VYUY8_2X8 || > + fmt.format.code == MEDIA_BUS_FMT_YVYU8_2X8) { > + dev_err(csi->dev, > + "Only UYVY input allowed for YUV422 8-bit. Output format can be configured.\n"); > + return -EPIPE; > + } > + > + if (fmt.format.code == MEDIA_BUS_FMT_UYVY8_2X8) { > + /* Format conversion between YUV422 formats can be done. */ > + if (ti_fmt->code != MEDIA_BUS_FMT_UYVY8_2X8 && > + ti_fmt->code != MEDIA_BUS_FMT_YUYV8_2X8 && > + ti_fmt->code != MEDIA_BUS_FMT_VYUY8_2X8 && > + ti_fmt->code != MEDIA_BUS_FMT_YVYU8_2X8) > + return -EPIPE; > + } else if (fmt.format.code != ti_fmt->code) { > + return -EPIPE; > + } > + > + if (fmt.format.field != V4L2_FIELD_NONE && > + fmt.format.field != V4L2_FIELD_ANY) > + return -EPIPE; > + > + return 0; > +} > + > +static int ti_csi2rx_start_streaming(struct vb2_queue *vq, unsigned int count) > +{ > + struct ti_csi2rx_dev *csi = vb2_get_drv_priv(vq); > + struct ti_csi2rx_dma *dma = &csi->dma; > + struct ti_csi2rx_buffer *buf, *tmp; > + unsigned long flags = 0; No need to assign flags here. > + int ret = 0; > + -- Kind regards, Sakari Ailus