diff mbox

[RFC] Infrared Keycode standardization

Message ID 20090828041459.67c1499a@pedra.chehab.org
State New, archived
Headers show

Commit Message

Mauro Carvalho Chehab Aug. 28, 2009, 7:14 a.m. UTC
Em Fri, 28 Aug 2009 00:46:28 -0300
Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:

> So, we need a sort of TODO list for IR changes. A start point (on a random
> order) would be something like:
> 
> 2) Implement a v4l handler for EVIOCGKEYCODE/EVIOCSKEYCODE;
> 3) use a different arrangement for IR tables to not spend 16 K for IR table,
> yet allowing RC5 full table;
> 4) Use the common IR framework at the dvb drivers with their own iplementation;
> 5) Allow getkeycode/setkeycode to work with the dvb framework using the new
> methods;

Ok, I have a code that handles the above for dvb-usb. Se enclosed. It turned to be
simpler than what I've expected originally ;)

Tested with kernel 2.6.30.3 and a dibcom device.

While this patch works fine, for now, it is just a proof of concept, since there are a few
details to be decided/solved for a version 2, as described bellow.

I'm committing at the development tree some improvements at keytable util for
it to handle those 16 bits tables



Cheers,
Mauro
---

dvb-usb: allow userspace replacement of IR keycodes

Implements handler for EVIOCGKEYCODE/EVIOCSKEYCODE via adding two new callbacks
to the input device.

Since on dvb-usb a scan code has 16 bits, to fulfill rc5 standard codes, the default
getkeycode/setkeycode input methods would require the driver to spend up to 64 Kb of
a sparse table. Instead, add two new callbacks to the event device.

With this, it is now possible to replace the keycode tables. There are, however, a few
implementation details at the current patch:

1) It will replace the existing device keytable, instead of creating an instance
of the data. This works. However, if two devices pointing to the same table
were connected, changing the IR table of one will also change the IR table for
the other (the solution for this one is simple: just kmalloc some memory);

2) In order to change the scan code, you need first to change the key to
KEY_RESERVED or KEY_UNKNOWN to free some space at the table (solution: allocate
some additional space for newer scan codes or allow dynamic table grow);

3) The table size cannot be extended. It would be easy to allow the table to
grow dynamically: just calling kmalloc(size+1); kfree(old). Yet, maybe we can
just create a bigger table with a fixed size, like for example a table with 128
entries. This should be enough even for a very big IR.

Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

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Comments

Peter Brouwer Aug. 28, 2009, 10:13 a.m. UTC | #1
Would like to add one more dimension to the discussion.

The situation of having multiple DVB type boards in one system.

Using one remote would be enough to control the system. So we should have a 
mechanism/kernel config option, to enable/disable an IR device on a board.
For multiple boards of the same type, enable the first and disable any 
subsequently detected boards.

Peter

> 

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Patrick Boettcher Aug. 28, 2009, 10:50 a.m. UTC | #2
Hi Mauro,

On Fri, 28 Aug 2009, Mauro Carvalho Chehab wrote:

> Em Fri, 28 Aug 2009 00:46:28 -0300
> Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:
>
>> So, we need a sort of TODO list for IR changes. A start point (on a random
>> order) would be something like:
>>
>> 2) Implement a v4l handler for EVIOCGKEYCODE/EVIOCSKEYCODE;
>> 3) use a different arrangement for IR tables to not spend 16 K for IR table,
>> yet allowing RC5 full table;
>> 4) Use the common IR framework at the dvb drivers with their own iplementation;
>> 5) Allow getkeycode/setkeycode to work with the dvb framework using the new
>> methods;
>
> Ok, I have a code that handles the above for dvb-usb. Se enclosed. It turned to be
> simpler than what I've expected originally ;)

Yeah, this is due to the nature of modularity of dvb-usb. Saying that, all 
drivers which have (re)implemented IR-handling needs to ported as well. Or 
included in dvb-usb :P .

> Tested with kernel 2.6.30.3 and a dibcom device.
>
> While this patch works fine, for now, it is just a proof of concept, since there are a few
> details to be decided/solved for a version 2, as described bellow.

This is the answer to the question I had several times in the past years.

Very good job. It will solve the memory waste in the driver for 
key-tables filled up with keys for different remotes where the user of 
one board only has one. The code will also be smaller and easier to read.

This also allows the user to use any remote with any (sensitive) 
ir-sensor in a USB device.

Is there a feature in 'input' which allows to request a file (like 
request_firmware)? This would be ideal for a transition from 
in-kernel-keymaps to user-space-keymap-loading: By default it would 
request the file corresponding to the remote delivered with the device.

Is that possible somehow?

Patrick.





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Mauro Carvalho Chehab Aug. 28, 2009, 12:30 p.m. UTC | #3
Em Fri, 28 Aug 2009 12:50:27 +0200 (CEST)
Patrick Boettcher <pboettcher@kernellabs.com> escreveu:

> Hi Mauro,
> 
> On Fri, 28 Aug 2009, Mauro Carvalho Chehab wrote:
> 
> > Em Fri, 28 Aug 2009 00:46:28 -0300
> > Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:
> >
> >> So, we need a sort of TODO list for IR changes. A start point (on a random
> >> order) would be something like:
> >>
> >> 2) Implement a v4l handler for EVIOCGKEYCODE/EVIOCSKEYCODE;
> >> 3) use a different arrangement for IR tables to not spend 16 K for IR table,
> >> yet allowing RC5 full table;
> >> 4) Use the common IR framework at the dvb drivers with their own iplementation;
> >> 5) Allow getkeycode/setkeycode to work with the dvb framework using the new
> >> methods;
> >
> > Ok, I have a code that handles the above for dvb-usb. Se enclosed. It turned to be
> > simpler than what I've expected originally ;)
> 
> Yeah, this is due to the nature of modularity of dvb-usb. 

Yes, but I was afraid that we would need to use a different struct for IR's.
This feature is already available for years at V4L, but the tables needed to
use scancode as their indexes to use the default handlers (I'm not sure, but
afaik, in the past there weren't ways to override them).

> Saying that, all 
> drivers which have (re)implemented IR-handling needs to ported as well. Or 
> included in dvb-usb :P .

My suggestion is to port the current implementation to ir-common.ko. This
module is not dependent of any other V4L or DVB specifics and has already
some code to handle GPIO polling based and GPIO IRQ based IR's. It contains
some IR tables for IR's that are used also on dvb-usb, like Hauppauge IR
keycodes.

Yet, we will need first to change ir-common.ko, since it is currently using the
tables indexed by a 7bit scancode (due to size constraints, V4L code discards
one RC5 byte), but this is already on our todo list (due to keycode
standardization).

> > Tested with kernel 2.6.30.3 and a dibcom device.
> >
> > While this patch works fine, for now, it is just a proof of concept, since there are a few
> > details to be decided/solved for a version 2, as described bellow.
> 
> This is the answer to the question I had several times in the past years.
> 
> Very good job. It will solve the memory waste in the driver for 
> key-tables filled up with keys for different remotes where the user of 
> one board only has one. The code will also be smaller and easier to read.
> 
> This also allows the user to use any remote with any (sensitive) 
> ir-sensor in a USB device.

True.

> Is there a feature in 'input' which allows to request a file (like 
> request_firmware)? This would be ideal for a transition from 
> in-kernel-keymaps to user-space-keymap-loading: By default it would 
> request the file corresponding to the remote delivered with the device.
> 
> Is that possible somehow?

There's nothing that I'm aware of, but I suspect that it shouldn't be hard to do it
via udev. 

We'll need to do some work there, in order to be sure that each V4L and DVB
device will have their own unique IR board ID's. We may then do an application
based on  v4l2-apps/util/keytable that will use the IR board ID to 
dynamically load the keytable, with a default config of loading the board's own
IR, but allowing the user to replace it by a custom one.

Currently, the Makefile at v4l2-apps/util creates a directory (keycodes) that
contains lots of IR tables. It does it by parsing the existing IR tables at V4L
side. After having all tables looking the same, it won't be hard to change it
to parse all MCE tables, creating an updated repository of the existing
scancode/keycode association.



Cheers,
Mauro
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Mauro Carvalho Chehab Aug. 28, 2009, 12:36 p.m. UTC | #4
Em Fri, 28 Aug 2009 11:13:33 +0100
Peter Brouwer <pb.maillists@googlemail.com> escreveu:

> 
> Would like to add one more dimension to the discussion.
> 
> The situation of having multiple DVB type boards in one system.
> 
> Using one remote would be enough to control the system. So we should have a 
> mechanism/kernel config option, to enable/disable an IR device on a board.
> For multiple boards of the same type, enable the first and disable any 
> subsequently detected boards.

I agree that this feature would be useful, but we shouldn't assume that the
user doesn't expect to have more than one IR working. With USB keyboard/mouse
and computers supporting video cards with multiple heads, it is possible to use
one server to handle several virtual machines with their own keyboard, mouse,
video and IR (in fact, I've already seen similar scenarios on some expositions).

Anyway, for this to happen with all drivers, the better way would be to use a
common IR framework.



Cheers,
Mauro
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Alistair Buxton Aug. 28, 2009, 2:22 p.m. UTC | #5
2009/8/28 Peter Brouwer <pb.maillists@googlemail.com>:
>
> Would like to add one more dimension to the discussion.
>
> The situation of having multiple DVB type boards in one system.
>
> Using one remote would be enough to control the system. So we should have a
> mechanism/kernel config option, to enable/disable an IR device on a board.
> For multiple boards of the same type, enable the first and disable any
> subsequently detected boards.

Don't forget that completely different boards can have identical
remotes. For example the RTL2831 driver has an almost identical copy
of dvb-usb IR code in it. See here for in depth explanation and patch
that makes it use dvb-usb instead:
http://patchwork.kernel.org/patch/38794/

Now I'm not really familiar with frontends and tuners so it may be
that the RTL driver should be reimplemented within dvb-usb instead,
but if it can't be it would be nice if that IR code could be shared
without pulling in all the rest of dvb-usb modules too. I'm told that
the excessive code duplication is the reason this driver isn't in
mainline yet - I've been using it with no problems for over two years
now.
Mauro Carvalho Chehab Aug. 29, 2009, 6:45 p.m. UTC | #6
Em Fri, 28 Aug 2009 09:30:42 -0300
Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:

> Em Fri, 28 Aug 2009 12:50:27 +0200 (CEST)
> Patrick Boettcher <pboettcher@kernellabs.com> escreveu:
> 
> > Hi Mauro,
> > 
> > On Fri, 28 Aug 2009, Mauro Carvalho Chehab wrote:
> > 
> > > Em Fri, 28 Aug 2009 00:46:28 -0300
> > > Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:
> > >
> > >> So, we need a sort of TODO list for IR changes. A start point (on a random
> > >> order) would be something like:
> > >>
> > >> 2) Implement a v4l handler for EVIOCGKEYCODE/EVIOCSKEYCODE;
> > >> 3) use a different arrangement for IR tables to not spend 16 K for IR table,
> > >> yet allowing RC5 full table;
> > >> 4) Use the common IR framework at the dvb drivers with their own iplementation;
> > >> 5) Allow getkeycode/setkeycode to work with the dvb framework using the new
> > >> methods;
> > >
> > > Ok, I have a code that handles the above for dvb-usb. Se enclosed. It turned to be
> > > simpler than what I've expected originally ;)
> > 
> > Yeah, this is due to the nature of modularity of dvb-usb. 
> 
> Yes, but I was afraid that we would need to use a different struct for IR's.
> This feature is already available for years at V4L, but the tables needed to
> use scancode as their indexes to use the default handlers (I'm not sure, but
> afaik, in the past there weren't ways to override them).
> 
> > Saying that, all 
> > drivers which have (re)implemented IR-handling needs to ported as well. Or 
> > included in dvb-usb :P .
> 
> My suggestion is to port the current implementation to ir-common.ko. This
> module is not dependent of any other V4L or DVB specifics and has already
> some code to handle GPIO polling based and GPIO IRQ based IR's. It contains
> some IR tables for IR's that are used also on dvb-usb, like Hauppauge IR
> keycodes.
> 
> Yet, we will need first to change ir-common.ko, since it is currently using the
> tables indexed by a 7bit scancode (due to size constraints, V4L code discards
> one RC5 byte), but this is already on our todo list (due to keycode
> standardization).

Ok, I've did several changes on both V4L and dvb-usb IR implementations. They
scancode tables are now implemented at the same way, at:
	http://linuxtv.org/hg/~mchehab/IR

I've also added there the current version of the getkeycode/setkeycode patch.

Ah, the v4l2-apps/util/Makefile will now generate the scancode userspace tables
for DVB IR's as well (currently, we have 85 IR layouts generated from source files).

What's still missing:

- For now, V4L is still using internally the old decoding process, based on the
7bit array of keycode.

- I haven't yet added some extra empty data at dvb scancode tables;

- although they're using the same structs, the code is still different.

Please review.



Cheers,
Mauro
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Mauro Carvalho Chehab Aug. 31, 2009, 5:47 a.m. UTC | #7
Em Sat, 29 Aug 2009 15:45:28 -0300
Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:

> Ok, I've did several changes on both V4L and dvb-usb IR implementations. They
> scancode tables are now implemented at the same way, at:
> 	http://linuxtv.org/hg/~mchehab/IR

Ok, I've also updated the V4L2 API spec with the default keyboard mapping on
the above URL. If nobody complains, I'll update our development tree with the
above changes likely today (Aug, 31) night, and prepare the changesets to be
added at linux-next.

Cheers,
Mauro
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Dmitry Torokhov Sept. 1, 2009, 1:38 a.m. UTC | #8
Mauro,

On Mon, Aug 31, 2009 at 02:47:41AM -0300, Mauro Carvalho Chehab wrote:
> Em Sat, 29 Aug 2009 15:45:28 -0300
> Mauro Carvalho Chehab <mchehab@infradead.org> escreveu:
> 
> > Ok, I've did several changes on both V4L and dvb-usb IR implementations. They
> > scancode tables are now implemented at the same way, at:
> > 	http://linuxtv.org/hg/~mchehab/IR
> 
> Ok, I've also updated the V4L2 API spec with the default keyboard mapping on
> the above URL. If nobody complains, I'll update our development tree with the
> above changes likely today (Aug, 31) night, and prepare the changesets to be
> added at linux-next.
> 

I see that you changed from KEY_KP* to KEY_*, unfortunately this change
will break users who have digits in upper register. KEY_KP* were not
perfect either since they are affected by NumLock state. I would
recommend moving to KEY_NUMERIC_* which should be unaffected by either
register, shift state or NumLock state.

Of course there is an issue of them being absent from most keymaps; but
nothing is perfect in thsi world ;)
diff mbox

Patch

diff -r ec87db9cb8db linux/drivers/media/dvb/dvb-usb/dvb-usb-remote.c
--- a/drivers/media/dvb/dvb-usb/dvb-usb-remote.c	Fri Aug 28 02:12:12 2009 -0300
+++ b/drivers/media/dvb/dvb-usb/dvb-usb-remote.c	Fri Aug 28 03:46:35 2009 -0300
@@ -12,6 +12,65 @@ 
 #include <linux/usb_input.h>
 #endif
 
+static int dvb_usb_getkeycode(struct input_dev *dev,
+				    int scancode, int *keycode)
+{
+	struct dvb_usb_device *d = input_get_drvdata(dev);
+
+	struct dvb_usb_rc_key *keymap = d->props.rc_key_map;
+	int custom = (scancode >> 8) & 0xff;
+	int data = scancode & 0xff;
+	int i;
+
+	/* See if we can match the raw key code. */
+	for (i = 0; i < d->props.rc_key_map_size; i++)
+		if (keymap[i].custom == custom &&
+			keymap[i].data == data) {
+			*keycode = keymap[i].event;
+			return 0;
+		}
+	return -EINVAL;
+}
+
+static int dvb_usb_setkeycode(struct input_dev *dev,
+				    int scancode, int keycode)
+{
+	struct dvb_usb_device *d = input_get_drvdata(dev);
+
+	struct dvb_usb_rc_key *keymap = d->props.rc_key_map;
+	int custom = (scancode >> 8) & 0xff;
+	int data = scancode & 0xff;
+	int i;
+
+	/* Search if it is replacing an existing keycode */
+	for (i = 0; i < d->props.rc_key_map_size; i++)
+		if (keymap[i].custom == custom &&
+			keymap[i].data == data) {
+			keymap[i].event = keycode;
+			return 0;
+		}
+
+	/* Search if is there a clean entry. If so, use it */
+	for (i = 0; i < d->props.rc_key_map_size; i++)
+		if (keymap[i].event == KEY_RESERVED ||
+		    keymap[i].event == KEY_UNKNOWN) {
+			keymap[i].custom = custom;
+			keymap[i].data = data;
+			keymap[i].event = keycode;
+			return 0;
+		}
+
+	/*
+	 * FIXME: Currently, it is not possible to increase the size of
+	 * scancode table. For it to happen, one possibility
+	 * would be to allocate a table with key_map_size + 1,
+	 * copying data, appending the new key on it, and freeing
+	 * the old one - or maybe just allocating some spare space
+	 */
+
+	return -EINVAL;
+}
+
 /* Remote-control poll function - called every dib->rc_query_interval ms to see
  * whether the remote control has received anything.
  *
@@ -127,6 +186,8 @@ 
 #else
 	input_dev->cdev.dev = &d->udev->dev;
 #endif
+	input_dev->getkeycode = dvb_usb_getkeycode;
+	input_dev->setkeycode = dvb_usb_setkeycode;
 
 	/* set the bits for the keys */
 	deb_rc("key map size: %d\n", d->props.rc_key_map_size);
@@ -144,6 +205,8 @@ 
 	input_dev->rep[REP_PERIOD] = d->props.rc_interval;
 	input_dev->rep[REP_DELAY]  = d->props.rc_interval + 150;
 
+	input_set_drvdata(input_dev, d);
+
 	err = input_register_device(input_dev);
 	if (err) {
 		input_free_device(input_dev);