From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Pawel Osciak <posciak@chromium.org>
Cc: Vincent Palatin <vpalatin@chromium.org>,
Hans de Goede <hdegoede@redhat.com>,
"linux-media@vger.kernel.org" <linux-media@vger.kernel.org>,
linux-kernel@vger.kernel.org, Olof Johansson <olofj@chromium.org>,
Zach Kuznia <zork@chromium.org>,
Mauro Carvalho Chehab <m.chehab@samsung.com>
Subject: Re: [PATCH v2] V4L: uvcvideo: Add support for relative pan/tilt controls
Date: Wed, 25 Jun 2014 11:54:30 +0200 [thread overview]
Message-ID: <8119752.rPOQIYa4Af@avalon> (raw)
In-Reply-To: <CACHYQ-rSk6etrX8RXF4w7aA_LJ9nzGtfJMOjhBOg49BZ4gaWgw@mail.gmail.com>
Hi Pawel,
On Wednesday 25 June 2014 11:46:24 Pawel Osciak wrote:
> On Tue, Jun 17, 2014 at 11:45 PM, Vincent Palatin wrote:
> > Map V4L2_CID_TILT_RELATIVE and V4L2_CID_PAN_RELATIVE to the standard UVC
> > CT_PANTILT_RELATIVE_CONTROL terminal control request.
> >
> > Tested by plugging a Logitech ConferenceCam C3000e USB camera
> > and controlling pan/tilt from the userspace using the VIDIOC_S_CTRL ioctl.
> > Verified that it can pan and tilt at the same time in both directions.
> >
> > Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
> >
> > Change-Id: I7b70b228e5c0126683f5f0be34ffd2807f5783dc
> > ---
> >
> > Changes
> > v2: fix control request name in description.
>
> The patch looks good, but I have a more general comment for everyone to
> consider. This doesn't match the expected functionality of
> controls V4L2_CID_PAN/TILT_RELATIVE. This is basically an on/off switch for
> pan/tilt, which once enabled will keep going until turned off (or I'm
> guessing until the maximum pan/tilt is reached), while the controls are
> supposed to expose an ability to turn the camera by a specified amount.
> Here the amount will also be ignored...
I agree with you here, and this mismatch between the V4L and UVC controls is
the reason why I haven't implemented relative pan/tilt support.
> Given that this is a standard UVC control, perhaps we need new V4L2
> controls for it, as I'm assuming we can't change the meaning of existing
> controls?
We could extend the meaning of the controls to cover the UVC behaviour in a
device-specific fashion, but that would be confusing for applications, so new
controls might be a better idea.
--
Regards,
Laurent Pinchart
next prev parent reply other threads:[~2014-06-25 9:53 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-17 0:38 [PATCH] V4L: uvcvideo: Add support for relative pan/tilt controls Vincent Palatin
2014-06-17 6:12 ` Hans de Goede
2014-06-17 14:45 ` [PATCH v2] " Vincent Palatin
[not found] ` <CACHYQ-rSk6etrX8RXF4w7aA_LJ9nzGtfJMOjhBOg49BZ4gaWgw@mail.gmail.com>
2014-06-25 9:54 ` Laurent Pinchart [this message]
2014-07-08 23:28 ` Vincent Palatin
2014-07-08 23:49 ` [PATCH 1/2] [media] V4L: Add camera pan/tilt speed controls Vincent Palatin
2014-07-08 23:49 ` [PATCH 2/2] V4L: uvcvideo: Add support for " Vincent Palatin
2014-09-03 4:57 ` Pawel Osciak
2014-09-03 19:40 ` [PATCH v3 " Vincent Palatin
2014-09-04 0:37 ` Pawel Osciak
2014-09-04 0:47 ` [PATCH v4 " Vincent Palatin
2014-09-04 20:29 ` Laurent Pinchart
2014-10-06 20:41 ` Vincent Palatin
2014-10-06 21:05 ` [PATCH v5 " Vincent Palatin
2014-10-07 16:36 ` Laurent Pinchart
2014-10-07 16:41 ` Vincent Palatin
2014-09-04 20:35 ` [PATCH v4 " Laurent Pinchart
2014-10-06 20:44 ` Vincent Palatin
2014-07-31 17:22 ` [PATCH 1/2] [media] V4L: Add camera " Vincent Palatin
[not found] ` <CACHYQ-o0FWSSHRmNhQ+id2uvHHWqVzQXQpmu31_e4OmDeVd_CQ@mail.gmail.com>
2014-08-06 15:10 ` Vincent Palatin
2014-08-07 2:18 ` Pawel Osciak
2014-08-08 16:41 ` Vincent Palatin
2014-08-15 19:08 ` [PATCH v2 " Vincent Palatin
2014-09-03 4:54 ` Pawel Osciak
2014-09-03 19:35 ` Vincent Palatin
2014-09-03 19:38 ` [PATCH v3 " Vincent Palatin
2014-10-06 21:04 ` [PATCH v5 " Vincent Palatin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=8119752.rPOQIYa4Af@avalon \
--to=laurent.pinchart@ideasonboard.com \
--cc=hdegoede@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-media@vger.kernel.org \
--cc=m.chehab@samsung.com \
--cc=olofj@chromium.org \
--cc=posciak@chromium.org \
--cc=vpalatin@chromium.org \
--cc=zork@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).