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LIRC Serial unusable on older PC R5.5 -RESOLVED-
http://forum.linhes.org/viewtopic.php?f=6&t=18637		 Page 1 of 1
Author:  cliffsjunk [ Thu Jul 24, 2008 6:38 pm ]
Post subject:  LIRC Serial unusable on older PC R5.5 -RESOLVED-
I have an Athlon 1400 MSI motherboard (VIA chip set KT266?)
PVR-350 system that is running R5F27 fairly well. The fairly
includes girlfriend having to reboot it maybe once a week due
to a funny "video double wide and/or colors whacked out" issue
that I have posted and seen others post about, and LIRC
missing the repeat code in the stream and sometimes (say 1 in
5) generating new presses because of it.

I threw a spare hard drive into this system and did a test install
of R5.5 to see if these issues might be resolved. The LIRC
issue is much worse. You might get one to three keypresses
to work (all in a short window?) once a minute. Unusable.

Anybody else seeing degraded LIRC performance in R5.5?

EDIT: Adding "acpi=force" to the "append=" options in /etc/lilo.conf
and running "lilo" (all as root) has fixed this issue.

Cliff
Author:  manicmike [ Thu Jul 24, 2008 6:58 pm ]
Post subject:  Re: LIRC Serial unusable on older PC R5.5
cliffsjunk wrote:
Anybody else seeing degraded LIRC performance in R5.5?


I have. There seems to be a USB conflict problem. Don't know if it's just 5.5. Am investigating now.

Mike
Author:  goofee [ Thu Jul 24, 2008 7:47 pm ]
Post subject: 
I was just looking into the same thing. I find the remote response a little irregular. Not as bad as your, mine is still usable. I'm finding these in my /var/log/messages
Code:
kernel: lirc_serial: ignoring spike: 1 1 4889260f 4888fcd2 759be 62dd6

I unplugged my USB wireless keyboard and it seemed to make it better but not 100%. When I tried to google it it seems that the signal is coming to fast so it ignores all of it. Seems weird cause it was fine before. Is there any way to change the setting on the serial port?
Author:  manicmike [ Thu Jul 24, 2008 8:00 pm ]
Post subject: 
goofee wrote:
Is there any way to change the setting on the serial port?


try "man setserial"

Mike
Author:  goofee [ Thu Jul 24, 2008 11:15 pm ]
Post subject: 
I found this in the known bug section on the lirc site. Not sure if this is what we are looking at or not. http://www.lirc.org/html/technical.html#bugs
Quote:
The lirc_serial and lirc_parallel drivers measure the time between interrupts on the serial resp. parallel port to get a pulse and space representation of the incoming infra-red signal. If interrupts are disabled by the CPU for a rather long time (>100 µs, which happens often e.g. during heavy IDE disk activity) some interrupts might get lost and the incoming data stream becomes disturbed. In this case decoding of the infra-red signal will fail. This is the downside of the really simple receiver circuits and can't be addressed in software except keeping the time where interrupts are disabled to a minimum.

If you are using an IDE system you might want to try calling hdparm -u1 -d1 for all of your drives. This enables DMA for the drive and allows the driver to unmask other interrupts during handling of a disk interrupt. But be aware that this can be dangerous for some (buggy) IDE chipsets. Consult the hdparm man page for further information.
Author:  elgordo123 [ Fri Jul 25, 2008 12:23 pm ]
Post subject: 
I'm using the one from http://www.irblaster.info/ and haven't had any problems at all, haven't seen any slowdown nor has it ever messed up a channel (yet).
Author:  cliffsjunk [ Mon Jul 28, 2008 9:38 pm ]
Post subject: 
goofee wrote:
hdparm -u1 -d1


This sounds like an excellent idea to try.

Cliff
Author:  cliffsjunk [ Tue Jul 29, 2008 11:59 am ]
Post subject: 
hdparm -u1 /dev/hda
hdparm -u1 /dev/hdc

did NOT help. As a matter of fact "u1" seems to be the default
in R5.5.

I did some careful timings of the periods when it works / doesn't
work and found that the period it works is about 1 to 2 seconds
followed by a period of 24-26 seconds where it doesn't work.

Anybody know of anything that goes off every 25-27 seconds?

Cliff
Author:  tjc [ Tue Jul 29, 2008 10:08 pm ]
Post subject: 
Not aside from watching "top" for a few minutes and seeing what bubbles to the top at that interval...
Author:  goofee [ Wed Jul 30, 2008 10:38 pm ]
Post subject: 
Sorry Cliff. I tried the hdparm trick earlier with the same no result but for some reason forgot to post back here.
Today I was snooping around on the lirc site again and there is supposed to be a -D switch to enable debugging. When I ran
Code:
lircd --help
it didn't show any options for debugging. It has to be compiled with --enable-debug to work. So I got the latest lirc-0.8.3. Here's where I probably screwed up. I started with
Code:
configure --enable-debug --with-driver=serial
make
I then remembered about the setup.sh that configures it for you. I ran it and enabled serial driver, with transmitter diode, debug, xtools.
Code:
make
make install
lirc-reconfigure
/etc/init.d/lirc stop
lircd -D3
pkill xinit

The result...The remote works perfectly. 8) never missed a keypress in irw or mythtv. But now my blaster on the same port isn't working. :( I'm thinking it's an lirc issue instead of some other hardware/software conflicting. Knoppmyth supports many remotes, so I assume that it would be configured --with-driver=all. Maybe it works better cause I only used the serial driver. The change log says lirc-0.8.3pre1 so maybe there are even issues in lirc itself.
At any rate I'm at a point where I need to do a reinstall for other issues so if anyone has suggestions or experiments they want to try, I'm prepared to hose my system.

Warren
Author:  cliffsjunk [ Thu Jul 31, 2008 9:31 am ]
Post subject:  RESOLVED
Adding "acpi=force" to the "append=" options in /etc/lilo.conf
and running "lilo" (all as root) has fixed this issue.

I have verified this several times. When I take it back out, the
problem comes back. When I put it in, the problem goes away.

I have a fairly old motherboard which provides acpi, but it's
date is before the "magic acpi date that Linux assumes for
acpi support". Apparently the fall back disables interrupts
a lot while it does whatever...

Cliff
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