Date:	Wed, 25 Nov 2009 22:50:00 -0500
From:	Andy Walls <awalls@...ix.net>
To:	Devin Heitmueller <dheitmueller@...nellabs.com>
Cc:	Jarod Wilson <jarod@...sonet.com>,
	Krzysztof Halasa <khc@...waw.pl>,
	Christoph Bartelmus <lirc@...telmus.de>,
	dmitry.torokhov@...il.com, j@...nau.net, jarod@...hat.com,
	linux-input@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-media@...r.kernel.org, mchehab@...hat.com, superm1@...ntu.com
Subject: Re: [RFC] Should we create a raw input interface for IR's ? - Was:
 Re: [PATCH 1/3 v2] lirc core device driver infrastructure

On Wed, 2009-11-25 at 13:20 -0500, Devin Heitmueller wrote:
> On Wed, Nov 25, 2009 at 1:07 PM, Jarod Wilson <jarod@...sonet.com> wrote:
> > Took me a minute to figure out exactly what you were talking about. You're referring to the current in-kernel decoding done on an ad-hoc basis for assorted remotes bundled with capture devices, correct?
> >
> > Admittedly, unifying those and the lirc driven devices hasn't really been on my radar.
> 
> This is one of the key use cases I would be very concerned with.  For
> many users who have bought tuner products, the bundled remotes work
> "out-of-the-box", regardless of whether lircd is installed.  I have no
> objection so much as to saying "well, you have to install the lircd
> service now", but there needs to be a way for the driver to
> automatically tell lirc what the default remote control should be, to
> avoid a regression in functionality.  We cannot go from a mode where
> it worked automatically to a mode where now inexperienced users now
> have to deal with the guts of getting lircd properly configured.
> 
> If such an interface were available, I would see to it that at least
> all the devices I have added RC support for will continue to work
> (converting the in-kernel RC profiles to lirc RC profiles as needed
> and doing the associations with the driver).
> 
> The other key thing I don't think we have given much thought to is the
> fact that in many tuners, the hardware does RC decoding and just
> returns NEC/RC5/RC6 codes.  And in many of those cases, the hardware
> has to be configured to know what format to receive.  We probably need
> some kernel API such that the hardware can tell lirc what formats are
> supported, and another API call to tell the hardware which mode to
> operate in.

Please think about how we would need to augment the v4l_subdev_ir_ops:

http://linuxtv.org/hg/v4l-dvb/file/74ad936bcca2/linux/include/media/v4l2-subdev.h#l246
http://linuxtv.org/hg/v4l-dvb/file/74ad936bcca2/linux/include/media/v4l2-subdev.h#l305
http://linuxtv.org/hg/v4l-dvb/file/74ad936bcca2/linux/include/media/v4l2-subdev.h#l27

I think encapsulation of the various IR devices under V4L-DVB into
v4l_subdevices can facilitate your suggestions.


The CX23888 IR subdevice code configures itself to a single default
setup for Tx and Rx:

http://linuxtv.org/hg/v4l-dvb/file/74ad936bcca2/linux/drivers/media/video/cx23885/cx23888-ir.c#l1192
http://linuxtv.org/hg/v4l-dvb/file/74ad936bcca2/linux/drivers/media/video/cx23885/cx23888-ir.c#l1211

but there isn't a reason V4L2 IR subdevices couldn't configure to a per
"product" defaults based on information about the detected card from the
main bridge driver code.

Regards,
Andy

> This is why I think we really should put together a list of use cases,
> so that we can see how any given proposal addresses those use cases.
> I offered to do such, but nobody seemed really interested in this.
> 
> Devin


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists