Using Perl to read Linux events

For a simple demo that played a movie on a BeagleBoard, I wanted to add a simple mechanism to start the movie over again if the USER button was pressed.

To read a Linux input event, it is as simple as just performing a read. The only trick to this for me, however, is that I wanted the read to timeout. This was resolved by using the Perl alarm() function can catching the signal within an eval().

I've uploaded a gist of my example play_movie.pl script:

Several OMAP/Beagle patches land upstream for Linux 2.6.33

I'm feeling pretty happy and excited today looking at the patches Linus Torvalds has recently merged into the Linux kernel mainline, such as a huge patch set from Tony Lindgren[1]. I'm particularly happy to see that DSS2 is there[2], so there shouldn't be any more confusion about what display driver to use on OMAP. The USB EHCI (host port) driver also finally got merged[5]. I also see a large number of power management patches being included.

Baseline support for several OMAP3 systems has also been included, including the Always Innovating Touch Book[3], AM3517 EVM[6], IGEPv2[7], CM-T35[8], OMAP3630 Zoom-3[9] and some updates for the OpenPandora[4]. Many of the OMAP3 development boards[10] and open development platforms are still not listed or easy to find in the Kconfig descriptions or board instance files.

A large number of bug fixes are also included.

It typically takes Linus 2-3 weeks to put together the first release candidate. After that, it typically takes 2-3 months to hammer out the bugs enough to make the the release. I'm looking forward to seeing great testing and contributions from the OMAP and BeagleBoard communities following the release of Linux 2.6.33-rc1!!

[1] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=9c3936cb694ffd559c80dc3eb75b61f769a39259
[2] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blob;f=Documentation/arm/OMAP/DSS
[3] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=7a079cab4632265fc87ee483daf57879d5dd87f2
[4] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=8d88f7f70cca3fa6aabac287fccd40cebacb92d1
[5] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=54ab2b02ef6a454b4cca969f546d0dd43fec7308
[6] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=c625327e2f5a506a89563e14ed837c82fa61548f
[7] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=58e111621d402d41cb0cabae7c532d6194b7d943
[8] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=2886d128d8ff83af88b9cbe6dbf7f0d2bbee8d76
[9] http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=5f35fbe8b8a05743fb9686e33194a126cd4273f6
[10] http://wiki.omap.com/index.php?title=OMAP3_Boards

Trade Show News

The Beagle Board will making a number of appearances over the next few weeks. Our very own Khasim Syed Mohammed will be at OSScamp July 19th in Bengaluru, India. In the UK, Koen Kooi and Måns Rullgård are looking to show off FFmpeg and Ångström at LugRadio Live on July 19-20.

A BeagleBoard fan group has shown up on Facebook. Currently, only the upcoming LinuxWorld Expo event in San Francisco August 4-7 is listed, but it is possible to RSVP to express interest in the BeagleBoard meet-up. I'm expecting for details on the meet-up to be provided shortly. I look forward to meeting you there!

The little things

It is the little things that make me happy sometimes, like Koen adding support for the Linux LED driver.

Several triggers are possible, such as accessing the NAND, MMC/SD, or just a regular heartbeat, as Koen has demonstrated. To list off the possible triggers for the LED driver:

root@beagleboard:~# cat /sys/class/leds/beagleboard\:\:led0/trigger
none nand-disk [mmc0] heartbeat timer

The above shows the MMC/SD access trigger enabled. Koen selected that by issuing the following command:

root@beagleboard:/sys/class/leds/beagleboard::led0# echo mmc0 > trigger

Get started adding your own drivers today by starting with the existing code and the kernel git tree. See http://elinux.org/BeagleBoard#Code (Thanks Dirk!) for references. The patch was discussed on the IRC channel here: http://www.beagleboard.org/irclogs/index.php?date=2008-05-30#T12:04:27.

Meanwhile, Sakoman and Khasim are continuing to to push ahead with the full NAND flash support. All these "little" activities really make me happy. :)

Beagle Board at LinuxTag!

Texas Instruments is hosting the BeagleBoard.org booth at LinuxTag 2008 on May 28-31. You will see Beagle board live demos and discuss open source topics at the booth - Hall 7.2a Stand 122. On Friday, May 30th, there is a two hour workshop about the open source project in workshop room 2 at noon. More information on the event can be found at http://www.linuxtag.org/2008/en/home/welcome.html.

Beagle patches integrated in upstream OMAP community Linux kernel

Thanks to Khasim Syed Mohammed, the recent OMAP community Linux kernel now contains basic patches for the Beagle board! For initial boot of Linux on Beagle you don't have to apply any additional patches, just download the community OMAP Linux kernel using git, do "make omap3_beagle_defconfig", and enjoy booting your new kernel on Beagle.

Khasim is just getting us started. Expect to see other community members contributing patches to provide additional functionality on the Beagle board soon.

Source released for the Beagle Board

Khasim has provided us with the first Linux sources and binaries for the Beagle Board. You can find them on the Beagle Board code.google.com page under BeagleSourceCode. Feel free to stop by the IRC channel (#beagle on irc.freenode.net) or the discussion group to learn more. Happy hacking!