On 30/01/2023 12:01, Dan Scally wrote:
Hi Laurent On 28/12/2022 02:33, Laurent Pinchart wrote:Hi Dan, Thank you for the patch. On Mon, Dec 19, 2022 at 02:43:13PM +0000, Daniel Scally wrote:As currently implemented the default color matching descriptor is appended after _all_ the formats and frames that the gadget is configured with. According to the UVC specifications however this is supposed to be on a per-format basis (section 3.9.2.6): "Only one instance is allowed for a given format and if present, the Color Matching descriptor shall be placed following the Video and Still Image Frame descriptors for that format." Associate the default color matching descriptor with struct uvcg_format and copy it once-per-format instead of once only. Signed-off-by: Daniel Scally <dan.scally@xxxxxxxxxxxxxxxx> --- Changes in v2: - Renamed uvcg_cmd and associated variables. - Formatting - Increased the refcnt variable for the color matching struct in the format make() functionsdrivers/usb/gadget/function/uvc_configfs.c | 64 +++++++++++++++++++++-drivers/usb/gadget/function/uvc_configfs.h | 13 +++-- 2 files changed, 68 insertions(+), 9 deletions(-)diff --git a/drivers/usb/gadget/function/uvc_configfs.c b/drivers/usb/gadget/function/uvc_configfs.cindex 147d3def24dd..6fb7ac8366fe 100644 --- a/drivers/usb/gadget/function/uvc_configfs.c +++ b/drivers/usb/gadget/function/uvc_configfs.c @@ -748,6 +748,29 @@ static const char * const uvcg_format_names[] = { "mjpeg", }; +static struct uvcg_color_matching * +uvcg_format_get_default_color_match(struct config_item *streaming) +{ + struct config_item *color_matching_item, *cm_default; + struct uvcg_color_matching *color_match; ++ color_matching_item = config_group_find_item(to_config_group(streaming),+ "color_matching"); + if (!color_matching_item) + return NULL; ++ cm_default = config_group_find_item(to_config_group(color_matching_item),+ "default"); + config_item_put(color_matching_item); + if (!cm_default) + return NULL; + + color_match = to_uvcg_color_matching(to_config_group(cm_default)); + config_item_put(cm_default); + + return color_match; +} +static ssize_t uvcg_format_bma_controls_show(struct uvcg_format *f, char *page){ struct f_uvc_opts *opts;@@ -1561,8 +1584,15 @@ static struct config_group *uvcg_uncompressed_make(struct config_group *group,'Y', 'U', 'Y', '2', 0x00, 0x00, 0x10, 0x00, 0x80, 0x00, 0x00, 0xaa, 0x00, 0x38, 0x9b, 0x71 }; + struct uvcg_color_matching *color_match; + struct config_item *streaming; struct uvcg_uncompressed *h; + streaming = group->cg_item.ci_parent; + color_match = uvcg_format_get_default_color_match(streaming); + if (!color_match) + return ERR_PTR(-EINVAL); + h = kzalloc(sizeof(*h), GFP_KERNEL); if (!h) return ERR_PTR(-ENOMEM);@@ -1580,6 +1610,8 @@ static struct config_group *uvcg_uncompressed_make(struct config_group *group,INIT_LIST_HEAD(&h->fmt.frames); h->fmt.type = UVCG_UNCOMPRESSED; + h->fmt.color_matching = color_match; + color_match->refcnt++;Does this need to be protected by a lock ? I suppose it may not matter too much for the default as it will never be dropped, but it would still be nice to get locking right overall.I don't think the locking is necessary here as in practice it's done by configfs core when you symlink between the config items. The refcnt here is only being used to protect a color matching descriptor's attributes from being changed when it's already been linked to a format, we rely on core to protect the descriptor from being dropped if it's in use somewhere.I'm tempted to increase the refcnt in uvcg_format_get_default_color_match(), as function that look up and return a pointer to a refcounted object should take a reference. That's not a hard requirement here if it makes the rest of the code too complex.
Sorry forgot to respond here; in fact it does take a reference the the colour matching descriptors config_item, through config_group_find_item() in configfs core.
config_group_init_type_name(&h->fmt.group, name, &uvcg_uncompressed_type);@@ -1744,8 +1776,15 @@ static const struct config_item_type uvcg_mjpeg_type = { static struct config_group *uvcg_mjpeg_make(struct config_group *group,const char *name) { + struct uvcg_color_matching *color_match; + struct config_item *streaming; struct uvcg_mjpeg *h; + streaming = group->cg_item.ci_parent; + color_match = uvcg_format_get_default_color_match(streaming); + if (!color_match) + return ERR_PTR(-EINVAL); + h = kzalloc(sizeof(*h), GFP_KERNEL); if (!h) return ERR_PTR(-ENOMEM);@@ -1761,6 +1800,8 @@ static struct config_group *uvcg_mjpeg_make(struct config_group *group,INIT_LIST_HEAD(&h->fmt.frames); h->fmt.type = UVCG_MJPEG; + h->fmt.color_matching = color_match; + color_match->refcnt++; config_group_init_type_name(&h->fmt.group, name, &uvcg_mjpeg_type); @@ -1909,7 +1950,8 @@ static inline struct uvc_descriptor_header enum uvcg_strm_type { UVCG_HEADER = 0, UVCG_FORMAT, - UVCG_FRAME + UVCG_FRAME, + UVCG_CMD,s/UVCG_CMD/UVCG_COLOR_MATCHING/}; /*@@ -1959,6 +2001,10 @@ static int __uvcg_iter_strm_cls(struct uvcg_streaming_header *h,if (ret) return ret; } + + ret = fun(f->fmt->color_matching, priv2, priv3, 0, UVCG_CMD); + if (ret) + return ret; } return ret;@@ -2014,6 +2060,12 @@ static int __uvcg_cnt_strm(void *priv1, void *priv2, void *priv3, int n,*size += frm->frame.b_frame_interval_type * sz; } break; + case UVCG_CMD: { + struct uvcg_color_matching *color_match = priv1; + + *size += sizeof(color_match->desc); + } + break; } ++*count;@@ -2099,6 +2151,13 @@ static int __uvcg_fill_strm(void *priv1, void *priv2, void *priv3, int n,frm->frame.b_frame_interval_type); } break; + case UVCG_CMD: { + struct uvcg_color_matching *color_match = priv1; + + memcpy(*dest, &color_match->desc, sizeof(color_match->desc)); + *dest += sizeof(color_match->desc); + } + break; } return 0;@@ -2138,7 +2197,7 @@ static int uvcg_streaming_class_allow_link(struct config_item *src,if (ret) goto unlock; - count += 2; /* color_matching, NULL */ + count += 1; /* NULL */ *class_array = kcalloc(count, sizeof(void *), GFP_KERNEL); if (!*class_array) { ret = -ENOMEM;@@ -2165,7 +2224,6 @@ static int uvcg_streaming_class_allow_link(struct config_item *src,kfree(data_save); goto unlock; }- *cl_arr = (struct uvc_descriptor_header *)&opts->uvc_color_matching;++target_hdr->linked; ret = 0;diff --git a/drivers/usb/gadget/function/uvc_configfs.h b/drivers/usb/gadget/function/uvc_configfs.hindex c7392c9b840e..174ee691302b 100644 --- a/drivers/usb/gadget/function/uvc_configfs.h +++ b/drivers/usb/gadget/function/uvc_configfs.h @@ -52,12 +52,13 @@ enum uvcg_format_type { }; struct uvcg_format { - struct config_group group; - enum uvcg_format_type type; - unsigned linked; - struct list_head frames; - unsigned num_frames; - __u8 bmaControls[UVCG_STREAMING_CONTROL_SIZE]; + struct config_group group; + enum uvcg_format_type type; + unsigned linked; + struct list_head frames; + unsigned num_frames; + __u8 bmaControls[UVCG_STREAMING_CONTROL_SIZE]; + struct uvcg_color_matching *color_matching; }; struct uvcg_format_ptr {
