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Applications can use this information >>> for debugging, resource monitoring, or making informed decisions >>> about buffer allocation strategies. >>> >>> Signed-off-by: Ming Qian >>> --- >> >> Not sure why not export these information by debugfs, or any benefit vs >> debugfs? > > There is also a on-going proposal that uses fdinfo. > > Nicolas > Thanks for the reminder about the ongoing fdinfo proposal. Just to confirm, you are referring to Detlev’s ongoing fdinfo proposal, specifically this series: https://lore.kernel.org/lkml/20260212162328.192217-1-detlev.casanova@collabora.com/ I will align my work with it and switch to using fdinfo. Once the show_fdinfo support from that series is merged, I will prepare the next revision of my patch accordingly. Regards, Ming >> >> Generanlly document should be first patch, then driver change. >> >> Frank >> >>> drivers/media/v4l2-core/v4l2-ctrls-defs.c | 8 ++++++++ >>> include/uapi/linux/v4l2-controls.h | 4 +++- >>> 2 files changed, 11 insertions(+), 1 deletion(-) >>> >>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-defs.c b/drivers/media/v4l2-core/v4l2-ctrls-defs.c >>> index 551426c4cd01..053db78ff661 100644 >>> --- a/drivers/media/v4l2-core/v4l2-ctrls-defs.c >>> +++ b/drivers/media/v4l2-core/v4l2-ctrls-defs.c >>> @@ -831,6 +831,7 @@ const char *v4l2_ctrl_get_name(u32 id) >>> case V4L2_CID_ALPHA_COMPONENT: return "Alpha Component"; >>> case V4L2_CID_COLORFX_CBCR: return "Color Effects, CbCr"; >>> case V4L2_CID_COLORFX_RGB: return "Color Effects, RGB"; >>> + case V4L2_CID_MEMORY_USAGE: return "Memory Usage"; >>> >>> /* >>> * Codec controls >>> @@ -1476,6 +1477,13 @@ void v4l2_ctrl_fill(u32 id, const char **name, enum v4l2_ctrl_type *type, >>> *min = 0; >>> *max = 0xffff; >>> break; >>> + case V4L2_CID_MEMORY_USAGE: >>> + *type = V4L2_CTRL_TYPE_INTEGER64; >>> + *flags |= V4L2_CTRL_FLAG_READ_ONLY; >>> + *min = 0; >>> + *max = S64_MAX; >>> + *step = 1; >>> + break; >>> case V4L2_CID_FLASH_FAULT: >>> case V4L2_CID_JPEG_ACTIVE_MARKER: >>> case V4L2_CID_3A_LOCK: >>> diff --git a/include/uapi/linux/v4l2-controls.h b/include/uapi/linux/v4l2-controls.h >>> index 68dd0c4e47b2..02c6f960d38e 100644 >>> --- a/include/uapi/linux/v4l2-controls.h >>> +++ b/include/uapi/linux/v4l2-controls.h >>> @@ -110,8 +110,10 @@ enum v4l2_colorfx { >>> #define V4L2_CID_COLORFX_CBCR (V4L2_CID_BASE+42) >>> #define V4L2_CID_COLORFX_RGB (V4L2_CID_BASE+43) >>> >>> +#define V4L2_CID_MEMORY_USAGE (V4L2_CID_BASE+44) >>> + >>> /* last CID + 1 */ >>> -#define V4L2_CID_LASTP1 (V4L2_CID_BASE+44) >>> +#define V4L2_CID_LASTP1 (V4L2_CID_BASE+45) >>> >>> /* USER-class private control IDs */ >>> >>> -- >>> 2.53.0 >>>