Memory Leak » MythTV

More resources on low-power computing

john — Sun, 17 Feb 2008 08:17:12 +0000

The Via Epia mini-ITX boards are some of the lowest power around. Epiacenter.com has a power simulator that’s good for comparing the differences in boards.

Although, I’ve noticed that the VB7001G board I’m using has inconsistent results on the calculator — 16.23 watts idle versus 13.92 in “network mode”. Take it for what it’s worth.

While I’m at it — first booted the Via VB7001G this evening. The sole purpose of this is for use as my main mail/web server as well as the mythtv backend. With a good power supply and a laptop HD for the primary (non-video) storage, I hope to have a box that idles at <30 watts. Then the power hog P4 system connected to the TV would only be booted as needed.

Using an el’cheepo power supply and an old Maxtor HDD pulled from the shelf, it’s currently idling along at 46 W. Not a bad start. I think there’s easily enough room for improvement to achieve the goal. Silent PC Review got their EN12000 board down to 17W at idle — mind you, they had a 5 W head start on me using a low-power variant of the C7 CPU (not to mention 20% slower, and ~300% more expensive).

Here’s a good review of popular 2.5″ notebook hard drives.

Update: With a 90W Pico Power supply + the tuner card and 1.25 TB of disk on-line (2 disks, one 250MB laptop, and one 3.5″ 1.0 TB Western Digital Caviar Green Power drives), the box is idling at a grand total of 25 watts (AC wall power)! Mission Accomplished.

There’s still some room to tweak that down a bit. The 1TB drive does not need to be spun-up full time. That should drop the idle power down a few extra watts.

Thinking …

john — Thu, 31 Jan 2008 02:31:48 +0000

If I get the bug to build a new MythBox. The Asus M2A-VM motherboard coupled with the 45 Watt AMD Athlon X2 BE2350 would make a nice low-power combo. This report shows total system power of 59 W idle, and 87 W max. Not shabby considering the 2.8Ghz P4 system serving this very web page is cooking at 100W idle and 160 W when it’s cranking.

At 40 watts difference, 24×7 totals to 28.8KWH a month — cutting at most $6.33 from my power bill (assuming it’s all coming off the $0.22/KWH rate tier — which I rarely hit).

Tough to justify the $75 mobo, + $85 cpu + $70 memory.

Update: Silent PC review got 35W from their test system at idle using a notebook HD. That’s starting to look encouraging…

Update 2: Argh — mobo has an ATI graphics chip. Most likely will not run mythtv.

MythTV unresponsive/lags with remote

john — Fri, 25 Jan 2008 00:13:03 +0000

Currently chasing this nagging issue: MythTV responds almost instantly when using the keyboard, but it lags (at best) when pressing a button on the remote. And it’s more than a lag, it actually seams to queue several button presses and then respond to each command all at once. Incidentally, this was never a problem prior to installing the PCHDTV 5500 capture card.

Running ‘irw’ before starting mythfrontend reveals that the raw output from lirc discretely captures each and every button press without any visible lag. However, after starting X, the remote becomes unresponsice. No solution (yet). Just links with some clues:

mythfrontend does no react on every remote/lirc ‘click’

MythTV mailing list thread: Where does the remote lag come from?

Most likely not the problem — since irw shows lirc working fine, but interesting none-the-less: Winfast DTV1000 Remote DVB Tuner Card — (towards the bottom — adjust kernel interrupt rate ‘HZ’ to 1000Hz).

And here’s an interesting one — indeed, ir_common is getting loaded by cx88xx (pchdtv5500 card).

Update: Christoph (lirc developer) indicates:

Debugging will be required for the capture card driver. Someone is
disabling interrupts too long. You should remove the driver for the
capture card to isolate the one that causes the problem.

Final Solution Update: (prompted by Jack’s comment)

Believe it or not, it turns out the problem was infrared noise/interference generated by my plasma TV. The reason it worked using irw was because the screen was black and not generating much IR. Coincidentally, I added the tuner card at about the same time I got the plasma TV — so, my capture card cause-effect assumption was all wrong!

The solution was to wrap the IR receiver with several layers of cellophane, which acts as a filter for the near-visible spectrum IR. Google the following words for other references:

plasma IR remote interference filter

This article recommends 6-8 layers of “Glad Press-n-seal” for the filter.

I didn’t believe this could be the problem till I threw a blanket over the TV and worked the remote while peaking behind the blanket — it worked perfectly.

pchdtv 5500 tuner card setup

john — Tue, 15 Jan 2008 18:15:19 +0000

The pcHDTV 5500 tv tuner capture card allows Linux users the ability to record television broadcasts using an antenna or from cable. Using MythTV the setup is fairly straight forward, at least, it should have been…

Once it is installed, the first thing is to get the listing service setup. Seams simple enough with not-for-profit Schedules Direct service (now that the zap2it freebie is gone). Signed up for an account and gave the info to myth. Upon trying to run ‘mythfilldatabase’, all I got were a bunch of “500 server error” responses from the Schedules Direct server. This less than helpful message was the result of not providing a “lineup”, which identifies exactly what listings you want it to deliver. For instance, I want all of the local broadcasts that I can pick up with an antenna in San Jose. Once that was resolved the capture card was able to complete a station scan and it was up and running.

However, the remote was now dead. LIRC had been previously setup and working fine using a home brew serial port infrared receiver on COM1. Debugging with ‘irw’ showed that all appeared correct — LIRC was happily accepting devices and running fine. But, firing up ‘irw’ gave no output when mashing buttons on the remote.

After much hair pulling, I finally yanked the 5500 tuner card out and, wouldn’t you know: LIRC worked just as it always had. As I suspected, the tuner card was conflicting with COM1. To prove my suspicion, I put the tuner card into a different PCI slot an everything worked perfectly.
I’m no expert on IRQ conflicts, but I think that just might be what it was.

LIRC Serial

john — Mon, 27 Nov 2006 09:59:23 +0000

It seams that everytime I install a new version of Fedora, I always have to fidget with LIRC to get the remote to work again. At one point I was making a symbolic link from /dev/lirc -> /dev/lircd (if I recall correctly) or some other sillyness in modprobe.conf to fix symptoms similar*[1] to this from /var/log/messages:

lircd-0.8.1-CVS[3637]: accepted new client on /dev/lircd
lircd-0.8.1-CVS[3637]: could not get file information for /dev/lirc0
lircd-0.8.1-CVS[3637]: default_init(): No such file or directory
lircd-0.8.1-CVS[3637]: caught signal

*[1] I say “similar” because this was the message resulting from not loading the kernel modules — “modprobe lirc_serial”. But, as I recall, it gives similar symptoms when /dev/lirc* isn’t happy.
So, once and for all, I’m going to document what works for me. I’m using a homebrew infared receiver connected to COM1 serial port. This setup has worked perfectly with FC3 and FC6 (skipped 4 and 5).
Relevant section of /etc/modprobe.conf. Note that the final line ‘install lirc …’ is wrapped (one line only)

# Lirc stuff
alias char-major-61 lirc_serial
options lirc_serial irq=4 io=0x3f8
install lirc_serial /bin/setserial /dev/ttyS0 uart none; /sbin/modprobe –ignore-install lirc_serial

Here’s the real fix for all the /dev/lirc* unhappiness I’d get after starting lirc, only to watch it die as soon as something tried to use it (like irw). Add the following option to /etc/sysconfig/lircd :

# Options to lircd
LIRCD_OPTIONS=”-d /dev/lirc0″

Since I’m using LIRC to control MythTV, here’s the /etc/lircd.conf for a Yamaha RAV352 Remote control (standard remote that shipped with RX-V2500 receiver) with the default “DVR/VCR2″ remote function active. This will probably work for many other Yamaha remotes:

begin remote

name yamaha_rav352_drv
bits 21
flags RC6|CONST_LENGTH
eps 30
aeps 100

header 2718 842
one 481 406
zero 481 406
gap 108872
toggle_bit 0

rc6_mask 0×10000

begin codes
POWER 0x0ECFF3
POWER 0x0FCFF3
REW 0x0ECFD6
REW 0x0FCFD6
FFWD 0x0ECFD7
FFWD 0x0FCFD7
PREV_CHAPTER 0x0ECFDE
PREV_CHAPTER 0x0FCFDE
NEXT_CHAPTER 0x0ECFDF
NEXT_CHAPTER 0x0FCFDF
REC 0x0ECFC8
REC 0x0FCFC8
STOP 0x0ECFCE
STOP 0x0FCFCE
PAUSE 0x0ECFCF
PAUSE 0x0FCFCF
PLAY 0x0ECFD3
PLAY 0x0FCFD3
CURSOR-UP 0x0ECFA7
CURSOR-UP 0x0FCFA7
CURSOR-DOWN 0x0ECFA6
CURSOR-DOWN 0x0FCFA6
CURSOR-LEFT 0x0ECFA5
CURSOR-LEFT 0x0FCFA5
CURSOR-RIGHT 0x0ECFA4
CURSOR-RIGHT 0x0FCFA4
ENTER 0x0ECFA3
ENTER 0x0FCFA3
TITLE 0x0ECF37
TITLE 0x0FCF37
MENU 0x0ECFAB
MENU 0x0FCFAB
RETURN 0x0ECF7C
RETURN 0x0FCF7C
DISPLAY 0x0ECFF0
DISPLAY 0x0FCFF0
AUDIO 0x0FCFB1
AUDIO 0x0ECFB1
1 0x0ECFFE
1 0x0FCFFE
2 0x0ECFFD
2 0x0FCFFD
3 0x0ECFFC
3 0x0FCFFC
4 0x0ECFFB
4 0x0FCFFB
5 0x0ECFFA
5 0x0FCFFA
6 0x0ECFF9
6 0x0FCFF9
7 0x0ECFF8
7 0x0FCFF8
8 0x0ECFF7
8 0x0FCFF7
9 0x0ECFF6
9 0x0FCFF6
0 0x0ECFFF
0 0x0FCFFF
end codes

end remote

Note that every button has 2 codes so the device can recognize a single button push from an extended button push. If you find that you have to push the remote button twice to get it to function, you are missing the second encoding set. And that’s it for configuration. Once it’s configured, just:

# modprobe lirc_serial

# service lircd start

# /usr/bin/irw

If irw runs, grab the remote and mash some buttons and it should print out messages. If irw dies immediately, there’s some other problem, and it’s time to investigate /var/log/messages to find out why.

Blue border around mplayer videos

john — Sat, 02 Sep 2006 09:59:04 +0000

I’ve been using MythTV for quite some time now as simple way to integrate music and video playback from a home theater PC. It’s a fine package that interfaces with a single remote to operate the entire entertainment center.

But, like most things linux based, it seams that there’s always some tweak needed to make things ideal. The astute reader may have noticed this post has already been given it’s own category — yes, expect more to come about MythTV. The first post for Myth is hardly worth mentioning, but since I just now had to go find the answer to this again, well, that’s grounds for posting here!! So, without further ado:

For whatever reason, mplayer always puts a blue border (line) around the upper and left edge of the video during playback. This annoyance can be simply removed by placing:

xvattr -a XV_COLORKEY -v 0

into the .kde/Autostart/myth-load.sh script that was borrowed from Jarod Wilson’s fantastic MythTV Setup guide.