Hi,
On 03/28/2012 11:12 AM, Laurent Pinchart wrote:
Hi Hans,
Thanks for the patch.
On Sunday 25 March 2012 13:56:49 Hans de Goede wrote:
Note the unused in this patch slave_ids addition to the mappings will get
used in a follow up patch to generate control change events for the slave
ctrls when their flags change due to the master control changing value.
Signed-off-by: Hans de Goede<hdegoede@xxxxxxxxxx>
---
drivers/media/video/uvc/uvc_ctrl.c | 33 +++++++++++++++++++++++++++++++++
drivers/media/video/uvc/uvcvideo.h | 4 ++++
2 files changed, 37 insertions(+)
diff --git a/drivers/media/video/uvc/uvc_ctrl.c
b/drivers/media/video/uvc/uvc_ctrl.c index 742496f..91d9007 100644
--- a/drivers/media/video/uvc/uvc_ctrl.c
+++ b/drivers/media/video/uvc/uvc_ctrl.c
[snip]
@@ -943,6 +961,8 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain
*chain, struct uvc_control_mapping *mapping,
struct v4l2_queryctrl *v4l2_ctrl)
{
+ struct uvc_control_mapping *master_map;
+ struct uvc_control *master_ctrl = NULL;
struct uvc_menu_info *menu;
unsigned int i;
int ret = 0;
@@ -958,6 +978,19 @@ static int __uvc_query_v4l2_ctrl(struct uvc_video_chain
*chain, if (!(ctrl->info.flags& UVC_CTRL_FLAG_SET_CUR))
v4l2_ctrl->flags |= V4L2_CTRL_FLAG_READ_ONLY;
+ if (mapping->master_id)
+ master_ctrl = uvc_find_control(chain, mapping->master_id,
+ &master_map);
As an optimization, do you think it would make sense to add a struct
uvc_contro *master_ctrl field to struct uvc_control_mapping, and fill it in
uvc_ctrl_init_ctrl() ? That would require a loop over the mappings at
initialization time, but would get rid of the search operation at runtime. The
master_ctrl->info.flags& UVC_CTRL_FLAG_GET_CUR check would be performed at
initialization time as well, and master_ctrl would be left NULL it the master
control doesn't support the GET_CUR query.
I've just tried to implement this, and it is a bit tricky:
1) The looking up of master_id cannot be done from uvc_ctrl_init_ctrl(), since
all the mappings of the entity need to be added before the lookup can be done,
making it necessary to add another loop to uvc_ctrl_init_device().
2) Not only the ctrl itself, but also the mapping needs to be cached in the
uvc_control_mapping, since we need both.
Looking closer at things, I've opted to implement a simpler optimization,
replacing the uvc_find_control with a __uvc_find_control, since the master
and it slaves are always part of the same entity. This means we still do
some searching runtime, but a lot less.
I'll send an updated patchset with this change in it soon.
Regards,
Hans
--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
