From: Mauro Carvalho Chehab <mchehab@redhat.com>
To: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Jon Smirl <jonsmirl@gmail.com>, Andy Walls <awalls@radix.net>,
Krzysztof Halasa <khc@pm.waw.pl>,
Christoph Bartelmus <lirc@bartelmus.de>,
dmitry.torokhov@gmail.com, j@jannau.net, jarod@redhat.com,
jarod@wilsonet.com, linux-input@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-media@vger.kernel.org,
maximlevitsky@gmail.com, stefanr@s5r6.in-berlin.de,
superm1@ubuntu.com
Subject: Re: [RFC] What are the goals for the architecture of an in-kernel IR system?
Date: Mon, 30 Nov 2009 07:57:53 -0200 [thread overview]
Message-ID: <4B139721.5030808@redhat.com> (raw)
In-Reply-To: <20091129190059.02c2a0ff@lxorguk.ukuu.org.uk>
Hi Alan,
Alan Cox wrote:
> Does it really make sense to put big chunks of protocol decoding crap for
> an interface which runs at about 1 character per second on a good day
> into the kernel ? Does it really make sense ot move 50K of code from user
> context to kernel context where it must meet strict security
> requirements, be extensively audited and cannot be paged. For embedded
> users will also have to be highly modular so no unused bits are loaded.
The same logic would apply to mouse, keyboards and serial consoles.
It is possible to move everything to userspace.
However, there are some reassons for they to be in kernelspace:
- you may need them during boot time;
- they are mandatory to allow the users interaction;
- you need low latency.
The same arguments apply to IR, especially on embedded devices: some devices,
like TVs, Set Top TV boxes and IPTV Set Top Boxes have IR as their primary
input device.
Also, as changing a digital TV or an IP TV channel requires to discard the current
MPEG stream and getting a newer one, and it requires a large time until you'll
be able to output something to the user, one of the needs is to handle IR keystrokes
(especially channel up/down) as fast as possible, to try to minimize the discomfort
of changing a channel.
Using an approach where you'll send a raw event to userspace, process there and return
back to kernel will increase the latency and can only be done after when loading
the SYSV runlevel stuff.
On the other hand, we already have IR decoding in-kernel. Most of the code are
at:
drivers/media/common/ir-functions.c
But there are also some other decoders at bttv, saa7134 and cx88 drivers.
In the case of drivers/media stuff, there common case is that the drivers have
support for both space/pulse decoding and in-hardware decoding. On both cases,
the scancode is converted to a keystroke via evdev. IMHO, we shouldn't really
consider dropping those decoders from kernel.
Cheers,
Mauro.
next prev parent reply other threads:[~2009-11-30 9:59 UTC|newest]
Thread overview: 358+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-11-27 15:57 [RFC] What are the goals for the architecture of an in-kernel IR system? Jon Smirl
2009-11-27 15:57 ` Jon Smirl
2009-11-27 16:57 ` Andy Walls
2009-11-27 17:29 ` Christoph Bartelmus
2009-11-27 17:29 ` Christoph Bartelmus
2009-11-27 17:49 ` Jon Smirl
2009-11-27 17:49 ` Jon Smirl
2009-11-27 19:03 ` Ferenc Wagner
2009-11-27 19:21 ` Jon Smirl
2009-11-27 19:21 ` Jon Smirl
2009-11-28 1:34 ` Dmitry Torokhov
2009-11-29 12:01 ` Christoph Bartelmus
2009-11-29 12:01 ` Christoph Bartelmus
2009-11-30 10:41 ` Mauro Carvalho Chehab
2009-11-30 19:49 ` Krzysztof Halasa
2009-11-30 21:35 ` Jon Smirl
2009-11-30 21:35 ` Jon Smirl
2009-12-01 7:45 ` Christoph Bartelmus
2009-12-01 7:45 ` Christoph Bartelmus
2009-12-01 11:38 ` Andy Walls
2009-12-01 14:10 ` Maxim Levitsky
2009-12-03 17:31 ` Krzysztof Halasa
2009-12-03 17:31 ` Krzysztof Halasa
2009-11-28 9:04 ` Simon Kenyon
2009-11-28 9:04 ` Simon Kenyon
2009-11-28 9:04 ` Simon Kenyon
2009-11-28 11:21 ` Mauro Carvalho Chehab
2009-11-29 11:50 ` Christoph Bartelmus
2009-11-29 11:50 ` Christoph Bartelmus
2009-11-30 12:34 ` Mauro Carvalho Chehab
2009-12-01 9:52 ` Gerd Hoffmann
2009-12-01 13:11 ` Mauro Carvalho Chehab
2009-12-01 14:32 ` Jarod Wilson
2009-12-01 10:20 ` Gerd Hoffmann
2009-12-01 14:14 ` Mauro Carvalho Chehab
2009-12-01 15:28 ` Gerd Hoffmann
2009-12-03 4:29 ` Jarod Wilson
2009-12-03 12:09 ` Gerd Hoffmann
2009-12-03 17:55 ` Dmitry Torokhov
2009-12-03 18:33 ` Mauro Carvalho Chehab
2009-12-04 10:06 ` Dmitry Torokhov
2009-12-04 14:12 ` Mauro Carvalho Chehab
2009-12-04 15:42 ` Jon Smirl
2009-12-04 15:42 ` Jon Smirl
2009-12-06 7:09 ` Dmitry Torokhov
2009-12-06 11:03 ` Mauro Carvalho Chehab
2009-12-06 20:19 ` Krzysztof Halasa
2009-12-08 0:00 ` Mauro Carvalho Chehab
2009-12-08 14:06 ` Krzysztof Halasa
2009-12-07 7:48 ` Dmitry Torokhov
2009-12-07 15:34 ` Mauro Carvalho Chehab
2009-12-07 18:34 ` Dmitry Torokhov
2009-12-07 23:01 ` Mauro Carvalho Chehab
2009-12-06 7:14 ` Dmitry Torokhov
2009-12-06 11:23 ` Mauro Carvalho Chehab
2009-12-03 18:56 ` Jon Smirl
2009-12-03 18:56 ` Jon Smirl
2009-12-03 18:56 ` Jon Smirl
2009-12-03 21:10 ` Mauro Carvalho Chehab
2009-12-03 21:51 ` Christoph Bartelmus
2009-12-03 21:51 ` Christoph Bartelmus
2009-12-03 22:12 ` Dmitry Torokhov
2009-12-04 7:37 ` Christoph Bartelmus
2009-12-04 7:37 ` Christoph Bartelmus
2009-12-04 14:33 ` Mauro Carvalho Chehab
2009-12-04 21:46 ` Christoph Bartelmus
2009-12-04 21:46 ` Christoph Bartelmus
2009-12-04 22:07 ` Dmitry Torokhov
2009-12-04 23:01 ` Christoph Bartelmus
2009-12-04 23:01 ` Christoph Bartelmus
2009-12-04 23:15 ` Dmitry Torokhov
2009-12-06 11:58 ` Christoph Bartelmus
2009-12-06 11:58 ` Christoph Bartelmus
2009-12-07 7:51 ` Dmitry Torokhov
2009-12-08 22:27 ` Christoph Bartelmus
2009-12-08 22:27 ` Christoph Bartelmus
2009-12-05 0:28 ` Jon Smirl
2009-12-05 0:28 ` Jon Smirl
2009-12-05 1:48 ` Andy Walls
2009-12-05 2:10 ` Andy Walls
2009-12-05 3:45 ` Jon Smirl
2009-12-05 3:45 ` Jon Smirl
2009-12-06 2:30 ` Andy Walls
2009-12-06 17:26 ` Krzysztof Halasa
2009-12-12 22:52 ` david
2009-12-06 3:36 ` hermann pitton
2009-12-06 6:55 ` Dmitry Torokhov
2009-12-06 11:46 ` Mauro Carvalho Chehab
2009-12-06 17:48 ` Krzysztof Halasa
2009-12-06 17:52 ` Jon Smirl
2009-12-06 17:52 ` Jon Smirl
2009-12-06 20:34 ` Krzysztof Halasa
2009-12-06 21:23 ` Jon Smirl
2009-12-06 21:23 ` Jon Smirl
2009-12-07 23:44 ` Mauro Carvalho Chehab
2009-12-08 0:28 ` Jon Smirl
2009-12-08 0:28 ` Jon Smirl
2009-12-08 0:28 ` Jon Smirl
2009-12-08 11:17 ` Mauro Carvalho Chehab
2009-12-08 13:34 ` Jon Smirl
2009-12-08 13:34 ` Jon Smirl
2009-12-08 13:34 ` Jon Smirl
2009-12-08 14:56 ` Mauro Carvalho Chehab
2009-12-08 22:25 ` Christoph Bartelmus
2009-12-08 22:25 ` Christoph Bartelmus
2009-12-08 17:04 ` Dmitry Torokhov
2009-12-08 13:54 ` Krzysztof Halasa
2009-12-08 4:23 ` Dmitry Torokhov
2009-12-08 11:58 ` Mauro Carvalho Chehab
2009-12-08 14:01 ` Krzysztof Halasa
2009-12-08 14:13 ` Mauro Carvalho Chehab
2009-12-08 15:26 ` Krzysztof Halasa
2009-12-08 15:41 ` Mauro Carvalho Chehab
2009-12-08 17:12 ` Dmitry Torokhov
2009-12-08 13:57 ` Krzysztof Halasa
2009-12-08 17:25 ` Dmitry Torokhov
2009-12-08 13:52 ` Krzysztof Halasa
2009-12-08 14:07 ` Mauro Carvalho Chehab
2009-12-08 14:51 ` Jon Smirl
2009-12-08 14:51 ` Jon Smirl
2009-12-08 15:29 ` Krzysztof Halasa
2009-12-08 15:49 ` Mauro Carvalho Chehab
2009-12-08 16:26 ` Jon Smirl
2009-12-08 16:26 ` Jon Smirl
2009-12-08 4:10 ` Andy Walls
2009-12-08 22:30 ` Christoph Bartelmus
2009-12-08 22:30 ` Christoph Bartelmus
2009-12-09 2:21 ` Andy Walls
2009-12-07 18:41 ` Dmitry Torokhov
2009-12-07 20:08 ` Krzysztof Halasa
2009-12-07 21:38 ` Dmitry Torokhov
2009-12-08 15:24 ` Krzysztof Halasa
2009-12-08 0:44 ` Jon Smirl
2009-12-08 0:44 ` Jon Smirl
2009-12-08 11:23 ` Mauro Carvalho Chehab
2009-12-13 12:14 ` Mauro Carvalho Chehab
2009-12-15 11:50 ` Pavel Machek
2009-12-15 13:33 ` Mauro Carvalho Chehab
2009-12-15 13:43 ` Jon Smirl
2009-12-15 13:43 ` Jon Smirl
2009-12-15 13:43 ` Jon Smirl
2009-12-15 14:19 ` Mauro Carvalho Chehab
2009-12-15 19:58 ` Pavel Machek
2009-12-15 20:14 ` Jon Smirl
2009-12-15 20:14 ` Jon Smirl
2009-12-15 20:19 ` Pavel Machek
2009-12-15 20:19 ` Pavel Machek
2009-12-15 20:29 ` Jon Smirl
2009-12-15 20:29 ` Jon Smirl
2009-12-15 20:33 ` Pavel Machek
2009-12-15 20:45 ` Jon Smirl
2009-12-15 20:45 ` Jon Smirl
2009-12-15 20:45 ` Jon Smirl
2009-12-15 21:05 ` Pavel Machek
2009-12-15 21:05 ` Pavel Machek
2009-12-15 21:38 ` Jon Smirl
2009-12-15 21:38 ` Jon Smirl
2010-03-25 14:42 ` Mauro Carvalho Chehab
2010-03-25 18:32 ` Pavel Machek
2010-03-25 19:00 ` Mauro Carvalho Chehab
2010-03-26 11:04 ` David Härdeman
2010-03-26 11:04 ` David Härdeman
2010-03-26 11:27 ` David Härdeman
2010-03-26 11:27 ` David Härdeman
2010-03-26 14:40 ` Mauro Carvalho Chehab
2010-03-26 14:40 ` Mauro Carvalho Chehab
2010-03-26 16:01 ` Dmitry Torokhov
2010-03-26 16:01 ` Dmitry Torokhov
2010-03-26 17:22 ` Mauro Carvalho Chehab
2010-03-26 19:07 ` David Härdeman
2010-03-26 19:07 ` David Härdeman
2010-03-26 22:37 ` Jon Smirl
2010-03-26 22:37 ` Jon Smirl
2010-03-26 22:37 ` Jon Smirl
2010-03-27 8:27 ` David Härdeman
2010-03-28 23:22 ` Mauro Carvalho Chehab
2010-03-28 23:22 ` Mauro Carvalho Chehab
2010-03-29 0:51 ` Mauro Carvalho Chehab
2010-03-30 11:01 ` David Härdeman
2010-03-31 6:01 ` Mauro Carvalho Chehab
2010-03-31 6:01 ` Mauro Carvalho Chehab
2010-03-30 11:09 ` David Härdeman
2010-03-30 11:09 ` David Härdeman
2010-03-30 12:43 ` Mauro Carvalho Chehab
2010-03-30 12:43 ` Mauro Carvalho Chehab
2010-03-26 12:23 ` David Härdeman
2010-03-26 15:17 ` Mauro Carvalho Chehab
2010-03-26 15:17 ` Mauro Carvalho Chehab
2010-03-26 19:21 ` David Härdeman
2010-03-26 19:21 ` David Härdeman
2010-03-27 5:56 ` Pavel Machek
2010-03-27 5:56 ` Pavel Machek
2010-04-09 7:21 ` James Hogan
2010-04-09 10:50 ` Andy Walls
2010-04-09 12:58 ` Jarod Wilson
2010-04-09 13:02 ` Jon Smirl
2010-04-09 13:02 ` Jon Smirl
2010-04-09 13:02 ` Jon Smirl
2010-04-09 13:01 ` Mauro Carvalho Chehab
2010-04-09 21:42 ` James Hogan
2010-04-09 21:55 ` Devin Heitmueller
2010-04-09 21:55 ` Devin Heitmueller
2010-04-09 22:14 ` Andy Walls
2010-04-09 23:32 ` Mauro Carvalho Chehab
2010-04-10 0:18 ` Jon Smirl
2010-04-10 0:18 ` Jon Smirl
2010-04-10 1:01 ` Mauro Carvalho Chehab
2010-04-10 0:38 ` hermann pitton
2009-12-07 15:36 ` Mauro Carvalho Chehab
2009-12-06 11:59 ` Christoph Bartelmus
2009-12-06 11:59 ` Christoph Bartelmus
2009-12-15 11:47 ` Pavel Machek
2009-12-06 12:12 ` Christoph Bartelmus
2009-12-06 12:12 ` Christoph Bartelmus
2009-12-06 16:38 ` Jon Smirl
2009-12-06 16:38 ` Jon Smirl
2009-12-06 16:38 ` Jon Smirl
2009-12-06 20:22 ` Krzysztof Halasa
2009-12-07 23:50 ` Mauro Carvalho Chehab
2009-12-03 23:45 ` Andy Walls
2009-12-03 17:47 ` Krzysztof Halasa
2009-11-27 21:49 ` Stefan Richter
2009-11-28 1:08 ` Maxim Levitsky
2009-11-28 11:20 ` Krzysztof Halasa
2009-11-28 14:42 ` Maxim Levitsky
2009-11-28 15:25 ` Krzysztof Halasa
2009-11-28 15:35 ` Maxim Levitsky
2009-11-28 15:44 ` Krzysztof Halasa
2009-11-28 16:26 ` Maxim Levitsky
2009-11-28 16:44 ` Krzysztof Halasa
2009-11-28 16:47 ` Christoph Bartelmus
2009-11-28 16:47 ` Christoph Bartelmus
2009-11-28 17:06 ` Jon Smirl
2009-11-28 17:06 ` Jon Smirl
2009-11-28 17:35 ` Krzysztof Halasa
2009-11-28 17:37 ` Jon Smirl
2009-11-28 17:37 ` Jon Smirl
2009-11-28 17:37 ` Jon Smirl
2009-11-28 17:40 ` Krzysztof Halasa
2009-11-28 17:40 ` Krzysztof Halasa
2009-11-28 23:26 ` Andy Walls
2009-11-29 4:58 ` Dmitry Torokhov
2009-11-29 20:27 ` Krzysztof Halasa
2009-11-29 20:44 ` Jon Smirl
2009-11-29 20:44 ` Jon Smirl
2009-11-29 20:44 ` Jon Smirl
2009-11-29 21:29 ` Dmitry Torokhov
2009-11-29 21:47 ` Jon Smirl
2009-11-29 21:47 ` Jon Smirl
2009-11-29 22:48 ` Dmitry Torokhov
2009-11-29 21:31 ` Dmitry Torokhov
2009-11-30 4:50 ` Jarod Wilson
2009-11-30 0:48 ` Andy Walls
2009-12-01 10:46 ` Gerd Hoffmann
2009-12-01 11:49 ` Andy Walls
2009-12-01 14:02 ` Gerd Hoffmann
2009-12-01 14:18 ` Mauro Carvalho Chehab
2009-11-30 17:45 ` Lennart Sorensen
2009-11-29 4:32 ` Andy Walls
2009-11-29 4:50 ` Dmitry Torokhov
2009-11-29 12:40 ` Alan Cox
2009-11-29 17:28 ` Maxim Levitsky
2009-11-29 17:49 ` Ray Lee
2009-11-29 17:49 ` Ray Lee
2009-11-29 18:13 ` Alan Cox
2009-11-29 18:52 ` Ray Lee
2009-11-29 18:52 ` Ray Lee
2009-11-29 19:04 ` Alan Cox
2009-11-29 19:16 ` Jon Smirl
2009-11-29 19:16 ` Jon Smirl
2009-11-29 19:29 ` Alan Cox
2009-11-29 19:49 ` Christoph Bartelmus
2009-11-29 19:49 ` Christoph Bartelmus
2009-11-30 0:05 ` Andy Walls
2009-11-29 23:35 ` Andy Walls
2009-11-30 2:15 ` Ray Lee
2009-11-30 2:15 ` Ray Lee
2009-11-30 2:15 ` Ray Lee
2009-11-30 9:58 ` Artur Skawina
2009-11-30 11:56 ` Mauro Carvalho Chehab
2009-11-30 12:57 ` Andy Walls
2009-11-30 13:23 ` Jon Smirl
2009-11-30 13:23 ` Jon Smirl
2009-11-30 13:23 ` Jon Smirl
2009-11-30 13:24 ` Mauro Carvalho Chehab
2009-11-30 16:14 ` kevin granade
2009-11-30 16:14 ` kevin granade
2009-11-30 17:33 ` Mauro Carvalho Chehab
2009-11-30 18:02 ` Dmitry Torokhov
2009-11-30 18:27 ` Mauro Carvalho Chehab
2009-11-30 19:07 ` Dmitry Torokhov
2009-11-30 20:07 ` Krzysztof Halasa
2009-11-30 13:43 ` Maxim Levitsky
2009-11-30 14:01 ` Jon Smirl
2009-11-30 14:01 ` Jon Smirl
2009-11-30 15:04 ` Maxim Levitsky
2009-11-30 16:19 ` Mauro Carvalho Chehab
2009-11-30 20:03 ` Krzysztof Halasa
2009-11-29 18:19 ` Jon Smirl
2009-11-29 18:19 ` Jon Smirl
2009-11-29 19:00 ` Alan Cox
2009-11-30 9:57 ` Mauro Carvalho Chehab [this message]
2009-11-28 18:17 ` Stefan Richter
2009-11-28 18:58 ` Jon Smirl
2009-11-28 18:58 ` Jon Smirl
2009-11-28 18:58 ` Jon Smirl
2009-11-28 19:45 ` Stefan Richter
2009-11-28 20:08 ` Jon Smirl
2009-11-28 20:08 ` Jon Smirl
2009-11-28 20:08 ` Jon Smirl
2009-11-28 20:21 ` Krzysztof Halasa
2009-12-12 19:33 ` Pavel Machek
2009-11-28 20:29 ` Stefan Richter
2009-11-28 20:34 ` Stefan Richter
2009-11-28 20:46 ` Jon Smirl
2009-11-28 20:46 ` Jon Smirl
2009-11-28 20:46 ` Jon Smirl
2009-11-28 21:46 ` Stefan Richter
2009-11-28 22:10 ` Jon Smirl
2009-11-28 22:10 ` Jon Smirl
2009-11-28 22:10 ` Jon Smirl
2009-11-28 22:18 ` Jon Smirl
2009-11-28 22:18 ` Jon Smirl
2009-11-29 4:59 ` Dmitry Torokhov
2009-11-29 16:01 ` Mauro Carvalho Chehab
2009-11-29 16:18 ` Mauro Carvalho Chehab
2009-11-29 11:24 ` Christoph Bartelmus
2009-11-29 11:24 ` Christoph Bartelmus
2009-11-29 16:01 ` Mauro Carvalho Chehab
2009-11-28 19:55 ` Krzysztof Halasa
2009-11-28 20:14 ` Jon Smirl
2009-11-28 20:14 ` Jon Smirl
2009-11-28 20:29 ` Krzysztof Halasa
2009-11-28 17:21 ` Krzysztof Halasa
2009-11-28 17:21 ` Krzysztof Halasa
2009-11-29 11:07 ` Christoph Bartelmus
2009-11-29 11:07 ` Christoph Bartelmus
2009-11-28 16:45 ` Jon Smirl
2009-11-28 16:45 ` Jon Smirl
2009-11-28 18:45 ` Maxim Levitsky
2009-11-28 18:56 ` Jon Smirl
2009-11-28 18:56 ` Jon Smirl
2009-11-28 19:16 ` Maxim Levitsky
2009-11-28 19:30 ` Stefan Richter
2009-11-28 19:32 ` Jon Smirl
2009-11-28 19:32 ` Jon Smirl
2009-11-28 19:48 ` Stefan Richter
2009-11-29 2:47 ` Mike Lampard
2009-11-29 4:55 ` Dmitry Torokhov
2009-11-29 5:31 ` Mike Lampard
2009-11-29 7:14 ` Dmitry Torokhov
2009-11-29 21:59 ` Artur Skawina
2009-11-30 12:13 ` Mauro Carvalho Chehab
2009-12-07 17:53 Emmanuel Fusté
2009-12-07 23:16 ` Mauro Carvalho Chehab
2009-12-07 17:54 Emmanuel Fusté
2009-12-07 18:24 ` Dmitry Torokhov
2009-12-08 9:31 ` Emmanuel Fusté
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