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Linux IR HOWTO: Troubleshooting, Mailing List

10. Troubleshooting, Mailing List

10.1 General Information

If you encounter problems. Try the following:

Read the FAQ section below.
Look at /var/log/messages and/or /var/log/kern.
Do a dmesg.
Look at the different files in /proc/irda.
Look at the mailing list archiv at http://www.ita.chalmers.se/~svinto/hypermail/irda/, whether your problem is already known.
Ask in the Linux/IrDA mailing list. To join the Linux-IrDA mailing list, send a mail to linux-irda-request@list.uit.no with "subscribe" in the email body. Use linux-irda@list.uit.no to post a message. You are welcome to use this mailing list for posting questions, answers, bug-reports, patches, suggestions and comments. To avoid spam, the list is now moderated, so there may be some time before your posting is distributed to the other list members.

10.2 Troubleshooting Techniques

Although I'm not much of a hacker I collected some tricks to track errors or bugs in the Linux/IrDA software.

You may set the debug level in /proc/sys/net/irda/debug to 1, 2, 3, 4.

Use the files in /proc/sys/net/irda to try different parameters like echo 0 > /proc/sys/net/irda/discovery. The /proc/*/irda files are:

root@duckman:~# ls /proc/sys/net/irda/* /proc/net/irda/*
/proc/net/irda/discovery        /proc/net/irda/irlmp            /proc/sys/net/irda/devname
/proc/net/irda/irda_device      /proc/net/irda/irttp            /proc/sys/net/irda/discovery
/proc/net/irda/irias            /proc/sys/net/irda/compression
/proc/net/irda/irlap            /proc/sys/net/irda/debug

It is also possible to debug the code. But I don't know how to do this. If you want to use SKB debug code, you may edit irda.h and change /include/linux/skbuff.h (see revision history of snapshot 10-2-98).
For problems with the irda module a utility from the modules package kdstat might be helpful. But I was not able to try this.
"You can now alter the number of discovery packets used (1, 6, 8 or 16) and the timeout between sending them (2-8 * 10 ms) in /proc/sys/net/irda. Please experiment if you have problems discovering your device. My Palm III seems to like 16 discovery_slots and 8 (*10 ms) for slot_timeout. " ... "The absolute minimum for reliable discovery of the IR-610 seems to be 9."
If anybody gets a kernel Oops, then please feed it to the ../linux/scripts/ksymoops/ksymoops program, so that we can find out where it went wrong. Just cut out the Oops lines from the syslog, save them to a file, and then run ksymoops <file>
Dag Brattli wrote: I found out that the cs4232 sound card was giving me several hundred interrupts per second! I removed the sound stuff from my kernel, and the machine is now generally about 4 times faster! Linux/IrDA may get problems if you are running the esound server (esd) on your machine. Both my machines, a 166Mhz Pentium laptop and a 200Mhz Pentium Pro cannot run Linux/IrDA when esd is running. The reason is that esd makes the soundcard give interrups over 300 times/second which makes the serial driver overrun when receiving. This is because the serial driver now uses slow interrupts in Linux-2.2 (everything is slow interrupts in 2.2), so the interrupt-handler schedules on its way out. The good thing about slow interrupts is that packets are delivered much faster, since you don't need to wait for the next timer-tick. The only exception for this is the pc87108 driver which works fine since it uses DMA and will only give a couple of interrupts per packet.


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