I recently got my hands on a new 
When it arrived I plugged it in and it showed up as 2 separate keyboards, each with about half of the buttons. This wasn’t a major problem as both where seamlessly merged by the Linux HAL keyboard layer and I was planning on wrapping the input with LIRC anyway. What was a problem was that for a few of the buttons I was not getting any key events. The missing buttons where:
- The Big Green Start Button
- Most of the menu buttons (TV, DVD, Music, Photos …)
- Teletex
- Red, Green, Yellow & Blue
Kernel work
I could have lived with out most of these apart from the Teletext and the colour buttons as these are use by the DVB-T service here in the UK to access the interactive content.I started to have a bit of hunt round online and found that there was already code in the Linux Kernel to support similar remotes. I was just about to start writing my own extention to support this one when I came across a patch that had been submitted about 2 week earlier. Details of the patch can be found here. There is some discusion between the submitter (Wayne Thomas) and the maintainer of the HID code (Dmitry Torokhov) saying that Dmitry would like to remove all the code that provides support for these types of remote now it was possible to achive the same thing with configuration files and udev. I followed the link about how to set up udev, but was unable to get even the “unkown” responses when running the monitoring program.
Given that I could not get the alternative to work it looked like the quickest way to get full support for the remote was going to mean applying the patch. Since the HID code is built into the Kernel I couldn’t just build it as a module to load into an existing Fedora Kernel, I was going to have to rebuild the whole thing. Rather than mess about pulling a raw source tree I decided to let rpmbuild do the heavy lifting since this would mean I ended up with a kernel that was a close as possible to what I already had. I downloaded the src rpm with yumdownloader. Yumdownloader doesn’t actually install the src rpm package so you need to then actually install the package
# yumdownloader kernel
# rpm -ivh kernel-2.6.31.12-174.2.22.fc12.src.rpm
The install will create a rpmbuild directory tree. This is used to do the compiling and packaging when the rpm is built using the rpmbuild command. The tree looks like this:
rpmbuild
|-BUILD
|-BUILDROOT
|-RPMS
|-SOURCES
|-SPECS
|-SRPMS
The source tar file and all the patch files end up in the SOURCE dir and the rpm spec file goes in the SPECS dir. Applying the patch is a 2 step process. Firstly we need to down load the patch file from patchwork site listed above,I saved that in to the SOURCE dir in a file called btc-remote.patch. Secondly we need to update the spec file to ensure
that the patch is applied. This requires adding 2 lines, one to identify the file with the patch and one to actually apply it.
...
Patch16570: futex-handle-user-space-corruption-gracefully.patch
Patch16580: partitions-use-sector-size-for-efi-gpt.patch
<span style="color: blue">Patch16590: btc-remote.patch</span>
%endif
BuildRoot: %{_tmppath}/kernel-%{KVERREL}-root
...
# enable IR receiver on Hauppauge HD PVR (v4l-dvb merge pending)
ApplyPatch hdpvr-ir-enable.patch
# tell usbhid to ignore all imon devices (sent upstream 2009.07.31)
ApplyPatch hid-ignore-all-recent-imon-devices.patch
<span style="color: blue">ApplyPatch btc-remote.patch</span>
# Add kernel KSM support
ApplyPatch linux-2.6-ksm.patch
ApplyPatch linux-2.6-ksm-updates.patch
...
I have created another patch to add these lines as I expect to have to apply this next time Fedora ships a new Kernel. I have submitted a Bugzilla to ask for this patch to be included in future releases. So with patch in the right place and the right bits in the spec file the rpms are built by executing the follow command from the rpmbuild dir
# rpmbuild -bb SPECS/kernel.spec
And remove the Fedora build package then install the new one with:
# yum erase kernel-2.6.31.12-174.2.22.fc12
# yum --nogpgcheck localinstall RPMS/kernel-2.6.31.12-174.2.22.fc12.i686.rpm
LIRC
After rebooting the system to the new Kernel all the buttons now work fine. Now rather than go throw all the applications mapping the keys to the required functions I chose to use LIRC to map the key presses to the functions. LIRC has a dev/input module that will take standard /dev/input/event devices as input. First we need to
stop the HAL layer from grabbing the devices and adding them to the normal keyboard inputs. Put the following in a file called 10-ignore-emprex in /etc/hal/fdi/preprobe
<?xml version="1.0" encoding="UTF-8"?>
<deviceinfo version="0.2">
<device>
<match key="info.product" contains_ncase="'BTC USB MCE Cordless Remote">
<merge key="info.ignore" type="bool">true</merge>
</match>
</device>
</deviceinfo>
Now we need to make sure we can indentify the /dev/input/event entries that map to the remote even if the order changes on boot. To do this we can use the udev rules. Looking in /proc/bus/input/device for the “BTC USB MCE Cordless Remote”, there will 2 entries looking a bit like this:
I: Bus=0003 Vendor=046e Product=5578 Version=0111
N: Name="BTC USB MCE Cordless Remote Control."
P: Phys=usb-0000:00:04.0-6/input1
S: Sysfs=/devices/pci0000:00/0000:00:04.0/usb2/2-6/2-6:1.1/input/input7
U: Uniq=
H: Handlers=kbd event7
B: EV=1f
B: KEY=837fff 2ff2b7 bf004444 0 0 1 f84 8a37c000 667bfa d941dfed 9e0000 0 0 0
B: REL=40
B: ABS=1 0
B: MSC=10
From this we can see that currently one of the 2 event sources is bound to event7, using this information udevadm tool a signature for the device that can be used to map the event devices to unique names.
# udevadm info -a -p $(udevadm info -q path -n /dev/input/event7)
Udevadm info starts with the device specified by the devpath and then
walks up the chain of parent devices. It prints for every device
found, all possible attributes in the udev rules key format.
A rule to match, can be composed by the attributes of the device
and the attributes from one single parent device.
looking at device '/devices/pci0000:00/0000:00:04.0/usb2/2-6/2-6:1.1/input/input7/event7':
KERNEL=="event7"
SUBSYSTEM=="input"
DRIVER==""
looking at parent device '/devices/pci0000:00/0000:00:04.0/usb2/2-6/2-6:1.1/input/input7':
KERNELS=="input7"
SUBSYSTEMS=="input"
DRIVERS==""
ATTRS{name}=="BTC USB MCE Cordless Remote Control."
ATTRS{phys}=="usb-0000:00:04.0-6/input1"
ATTRS{uniq}==""
ATTRS{modalias}=="input:b0003v046Ep5578e0111-e0,1,2,3,4,k71,72,73,74,77,80,82,83,85,86,87,88,89,
8A,8B,8C,8E,8F,90,96,98,9B,9C,9E,9F,A1,A3,A4,A5,A6,A7,A8,A9,AB,AC,AD,AE,B1,B2,B5,B6,CE,CF,D0,D1,D2,D5,
D9,DB,DF,E2,E7,E8,E9,EA,EB,100,162,166,16A,16E,178,179,17A,17B,17C,17D,17F,180,181,182,185,18C,18D,192,
193,195,1A0,1A1,1A2,1A3,1A4,1A5,1A6,1A7,1A8,1A9,1AA,1AB,1AC,1AD,1AE,1B0,1B1,1B7,r6,a20,m4,lsfw"
...
Using this and the instructions from the How to write udev rules I built the following file /etc/udev/rules.d/99-emprex.rules
KERNEL=="event[0-9]*", ATTRS{name}=="BTC USB MCE C*", ATTRS{phys}=="usb-0000:00:04.0-6/input0", SYMLINK+="input/rfremote0"
KERNEL=="event[0-9]*", ATTRS{name}=="BTC USB MCE C*", ATTRS{phys}=="usb-0000:00:04.0-6/input1", SYMLINK+="input/rfremote1"
This adds 2 symlinks to the /dev/input directory called rfremote0 and rfremote1. Using these 2 instances of lircd can be started to read both sets of inputs and pass them to the applications. To bind the lircd instance you need to start one with –listen and one with –connect as follows:
# lircd --driver=dev/input --device=/dev/input/rfremote0 --pidfile=/var/run/lirc/lircd0.pid --listen
# lircd --driver=dev/input --device=/dev/input/rfremote1 --pidfile=/var/run/lirc/lircd1.pid --connect=localhost:8765
Once these 2 instances are up and running irw can be used to test the input and also to build the .lircrc file
# Play
begin
prog = mythtv
button = KEY_PLAY
config = Return
end
# Stop
begin
prog = mythtv
button = KEY_STOPCD
config = I
end
# Escape/Exit/Back
begin
prog = mythtv
button = KEY_BACK
config = Esc
end
...
begin
prog = xine
button = KEY_PLAY
repeat = 3
config = Play
end
begin
prog = xine
button = KEY_STOPCD
repeat = 3
config = Stop
end
begin
prog = xine
button = KEY_BACK
repeat = 3
config = Quit
end
Now we are all good to go.
Resources
- LIRC – http://lirc.org/
- btc-remote.patch
- kernel.patch
- How to write udev rules – http://www.reactivated.net/writing_udev_rules.html
- MythTV and Xine .lircrc file – .lircrc
- Fedora Bugzilla – 567151
