How-to serial port tuning?

[bcjenkins]

THIS PROBLEM SEEMS TO NOW BE RESOLVED

If you are using USB to serial in multiples (4 for me) and have issues with device mappings remaining consistent, see http://forums.sagetv.com/forums/show...9&postcount=16 for my udev rules and script.

B

PS - Leaving the error codes in post for searching.

Running Ubuntu 7.04 Server

Error:

Wed 8/8 22:31:54.043 ERROR loading DirecTVSerialControl:java.lang.UnsatisfiedLinkError: no DirecTVSerialControl in java.library.path

I resolved that by linking to the file from /opt/sagetv/server.

Now when trying to tune; I see this in the log:

Wed 8/8 23:05:34.216 DTVSerial opened handle on port COM1
Wed 8/8 23:05:34.216 DTVSerial testing to see if baud rate is 115200...
Wed 8/8 23:05:34.216 DTVSerial failed at 115200, reverting to 9600 baud.
Wed 8/8 23:05:34.216 DTVSerial failed writing, num=-1
Wed 8/8 23:05:34.216 DTVSerialX num=-1 cmd[0]=0xfa.
Wed 8/8 23:05:34.216 Incomplete COM Write on handle 49
Wed 8/8 23:05:34.216 DTVSerial opened handle on port COM1
Wed 8/8 23:05:34.216 DTVSerial testing to see if baud rate is 115200...
Wed 8/8 23:05:34.216 DTVSerial failed at 115200, reverting to 9600 baud.
Wed 8/8 23:05:34.216 DTVSerial failed writing, num=-1
Wed 8/8 23:05:34.216 DTVSerialX num=-1 cmd[0]=0xfa.
Wed 8/8 23:05:34.216 Incomplete COM Write on handle 49

My serial port is on /dev/ttyUSB0 and I deleted and recreated /dev/ttyS0 as a link to it. What does COM1 mean in linux?

TIA

B

[_Demo_]

COM1 is mapped to ttyS0 like you expected.

_Demo_

[bcjenkins]

Is there a way to change the mapping, or can I symlink like I did? I just switched my main box from 2K3 to linux, and all this was working fine in windows.

Also, is there a way to make the default baud rate 9600?

TIA

B

[_Demo_]

Creating a symlink should be fine. There is no way to specify a default rate of 9600 but it already falls back to 9600 when 115200 fails.

_Demo_

[bcjenkins]

Upon reboot the /dev/ttyS0 symlink is destroyed and the node is put back. Is there a way to change the COM1 definition to be /dev/ttyUSB0?

TIA

B

[jpappas]

Most current Linux distros use udev for device file management.

You can add a rule to one of the /etc/udev/rules.d files (probably 98-local.rules or similar)

Example rule:
KERNEL=="ttyUSB*", SYMLINK+="ttyS%n"

This will add a symlink for all numbered ttyUSB to ttyS. You could also create a link based on the serial number or product name or whatever. See tutorial below.

A good tutorial on udev rules:
http://www.reactivated.net/writing_udev_rules.html

HTH,
John

[bcjenkins]

Thanks for that. According to /var/log/udev it set up a symlink on S0.

UDEV [1186712657.836195] add /class/tty/ttyUSB0 (tty)
UDEV_LOG=3
ACTION=add
DEVPATH=/class/tty/ttyUSB0
SUBSYSTEM=tty
SEQNUM=2659
MAJOR=188
MINOR=0
UDEVD_EVENT=1
DEVNAME=/dev/ttyUSB0
DEVLINKS=/dev/ttyS0

We'll see if it tests out.

B

Still isn't tuning.

Thu 8/9 22:29:36.721 Found next seq hdr code!
Thu 8/9 22:29:40.959 Loading 8x7 image from file /opt/sagetv/server/STVs/SageTV3/OSDStatusPlay.png
Thu 8/9 22:30:00.028 Incomplete COM Write on handle 71
Thu 8/9 22:30:00.028 DTVSerial opened handle on port COM1
Thu 8/9 22:30:00.028 DTVSerial testing to see if baud rate is 115200...
Thu 8/9 22:30:00.028 DTVSerial failed at 115200, reverting to 9600 baud.
Thu 8/9 22:30:00.028 DTVSerial failed writing, num=-1
Thu 8/9 22:30:00.028 DTVSerialX num=-1 cmd[0]=0xfa.
Thu 8/9 22:30:00.028 Incomplete COM Write on handle 71
Thu 8/9 22:30:00.035 switch encoding /var/media/tv/Roseanne-LikeaVirgin-72536-0.mpg
Thu 8/9 22:30:00.225 Found next seq hdr code!
Thu 8/9 22:30:09.954 Incomplete COM Write on handle 71
Thu 8/9 22:30:09.954 DTVSerial opened handle on port COM1
Thu 8/9 22:30:09.954 DTVSerial testing to see if baud rate is 115200...
Thu 8/9 22:30:09.954 DTVSerial failed at 115200, reverting to 9600 baud.
Thu 8/9 22:30:09.954 DTVSerial failed writing, num=-1
Thu 8/9 22:30:09.954 DTVSerialX num=-1 cmd[0]=0xfa.
Thu 8/9 22:30:09.954 Incomplete COM Write on handle 71
Thu 8/9 22:30:09.999 switch encoding /var/media/tv/TheAdventuresofJimmyNeutronBoyGenius-Stranded-388746-0.mpg
Thu 8/9 22:30:10.234 Found next seq hdr code!
Thu 8/9 22:30:49.625 Incomplete COM Write on handle 71
Thu 8/9 22:30:49.625 DTVSerial opened handle on port COM1
Thu 8/9 22:30:49.625 DTVSerial testing to see if baud rate is 115200...
Thu 8/9 22:30:49.625 DTVSerial failed at 115200, reverting to 9600 baud.
Thu 8/9 22:30:49.625 DTVSerial failed writing, num=-1
Thu 8/9 22:30:49.625 DTVSerialX num=-1 cmd[0]=0xfa.
Thu 8/9 22:30:49.625 Incomplete COM Write on handle 71
Thu 8/9 22:30:49.637 switch encoding /var/media/tv/Roseanne-LikeaVirgin-72536-1.mpg
Thu 8/9 22:30:49.770 Found next seq hdr code!

[bcjenkins]

So here's the deal..

I can't use just ttyS%n because it tries to link to an existing node. I tried using ttyS1% to register S10-S13 but is seems there is an artificial cap on how many ports the plugin will support. So the question is:

Can I write a udev rule like:

KERNEL=="ttyUSB*", SYMLINK+="ttyS{%n+4}"

and have it resolve to ttyS4-7 (4 usb adapters)

Failing this, I will add a ln -s /dev/ttyUSB0 /dev/ttyS4-7 to the startsage script. Although it seems silly to do so.

B

[bcjenkins]

Well, if anyone knows a simpler way, I am all ears. I wrote the following rule:

KERNEL=="ttyUSB*", PROGRAM="/opt/sagetv/server/ttyUSB_converter %n", SYMLINK+="ttyS%c"

Which runs the little bit of code:

#!/bin/bash
echo $[4+$1]

Which produced:

lrwxrwxrwx 1 root root 7 2007-08-10 16:51 /dev/ttyS4 -> ttyUSB0

What a pain!

Now on to tuning..

B

Which doesn't work!~ It hung at tuning and log indicated the tuning attempt stating it was stepping down the speed..

I let it sit for 5 mins, killed the PS window and the error log filled up with messages about the broken pipe. FYI - if I use the directv.pl from Myth, I can interact with the box all day long.

[jpappas]

Since it seems that you have a large number of usb devices, I suggest that you use the serial number(s) of the devices to define a "static" device mapping via udev. For each device, use the device's serial number to define the device name.

ie: BUS=="usb", SYSFS{serial}=="L72010011070626380", SYMLINK+="epson_680"

Does that seem to be a workable solution?

John

[bcjenkins]

Hi John,

Actually there isn't a serial number for each device. A coworker and I had this discussion last week. About the only thing unique is the following:

looking at parent device '/devices/pci0000:00/0000:00:1d.0/usb3/3-2/3-2:1.0'
KERNELS=="3-2:1.0"

Device list attached.

If I can key off the parent device, then I can tie the ttyUSB# to the physical port it is plugged in to. I was going to test a reboot this morning to see if the numbering remains the same. I assume udev is processing in a 1-n order by default.

B

[bcjenkins]

Now I know what my wife feels like after child birth!

Serial tuning is functioning, not sure how reliable yet because everytime I reboot the ttyUSB devices are moved around. Very annoying!

To resolve the serial tuning, I installed the kernel headers and downloaded a matching source from kernel.org. Side note, for some reason I could not easily find the right kernel source for Ubuntu.

1. uname -r to determine kernel version
2. download full source from kernel.org
3. cp pl2303.h and pl2303.c to directory in ~/
4. edit pl2303.c and look for: case B115200: baud = 115200; break;
5. Change to case B115200: baud = 9600; break;
6. Create custom Makefile

   obj-m    := pl2303.o
   
   KDIR    := /lib/modules/$(shell uname -r)/build
   PWD    := $(shell pwd)
   
   default:
   	$(MAKE) -C $(KDIR) SUBDIRS=$(PWD) modules

7. make
8. install the module

   sudo install -m 644 pl2303.ko /lib/modules/2.6.20-15-server/kernel/drivers/usb/serial/pl2303.ko

9. modprobe -r pl2303
10. modprobe pl2303

This basically drops the baud rate down to 9600 for requests going in at 115200. I will go back to default drivers once SageTV figures out why it is hanging.

Since my USB devices seem to be non-unique, I think I can solve this by putting them all on one hub. Then I can make the nodes based on hub port number.

[_Demo_]

Can you try the attached version without using your modified driver?

Thanks

_Demo_

[bcjenkins]

Tue 8/14 20:01:49.076 DTVSerial opened handle on port COM5
Tue 8/14 20:01:49.076 DTVSerial testing to see if baud rate is 115200...
Tue 8/14 20:01:49.578 DTVSerial response num=0 cmd[0]=0xfa cmd[1]=0x84 cmd[2]=0xc5 cmd[3]=0xb3 cmd[4]=0x44 cmd[5]=0x2b
Tue 8/14 20:01:49.578 DTVSerial failed at 115200, reverting to 9600 baud.

/opt/sagetv/server/irtunerplugins/libDirecTVSerialControl.so:
        linux-gate.so.1 =>  (0xffffe000)
        libstdc++.so.6 => /usr/lib/libstdc++.so.6 (0xb7ec8000)
        libm.so.6 => /lib/tls/i686/cmov/libm.so.6 (0xb7ea1000)
        libgcc_s.so.1 => /lib/libgcc_s.so.1 (0xb7e94000)
        libc.so.6 => /lib/tls/i686/cmov/libc.so.6 (0xb7d53000)
        /lib/ld-linux.so.2 (0x80000000)

Are there any other debugs I can turn on for info?

B

[_Demo_]

Could you try the latest beta version and tell me the results. It has updated file.

Thanks

_Demo_

[bcjenkins]

Sun 8/19 11:18:34.936 DTVSerial opened handle on port COM6
Sun 8/19 11:18:34.936 DTVSerial testing to see if baud rate is 115200...
Sun 8/19 11:18:35.435 DTVSerial response num=0 cmd[0]=0xfa cmd[1]=0x84 cmd[2]=0xca cmd[3]=0xb3 cmd[4]=0x44 cmd[5]=0x8b
Sun 8/19 11:18:35.435 DTVSerial failed at 115200, reverting to 9600 baud.
Sun 8/19 11:18:35.455 DTVSerialX num=1 cmd[0]=0x0.
Sun 8/19 11:18:35.455 DTVSerial Unknown Command Response on handle 82 of 0x4
Sun 8/19 11:18:35.739 DTVSerial opened handle on port COM6
Sun 8/19 11:18:35.739 DTVSerial testing to see if baud rate is 115200...
Sun 8/19 11:18:36.239 DTVSerial response num=0 cmd[0]=0xfa cmd[1]=0x84 cmd[2]=0xca cmd[3]=0xb3 cmd[4]=0x24 cmd[5]=0x8d
Sun 8/19 11:18:36.239 DTVSerial failed at 115200, reverting to 9600 baud.
Sun 8/19 11:18:36.260 DTVSerialX num=1 cmd[0]=0xf2.
Sun 8/19 11:18:36.260 DTVSerial got a command error, switching to other base for handle
Sun 8/19 11:18:36.270 DTVSerial Valid Command Recognized for handle 82
Sun 8/19 11:18:36.290 DTVSerial Set Top is Processing Request for handle 82
Sun 8/19 11:18:36.290 DTVSerial Unknown Command Response on handle 82 of 0xf5

Channel changing seems to be functioning (THANKS! ), I will have to perform a more careful analysis. The boxes I have are D11-100s is there something to be done about the last log entry?

However, my USB to serial adapter scripts needed some further work.. Previously, I tried plugging all 4 devices into a cheap USB 2.0 hub I had. I think it was too much so I had to put 2 of them back on to the standard ports. At least now though I have a unique way to identify each pair of devices. Also each pair loads in the same order every time. Without further ado:

bash script called by udev rules:

#!/bin/bash

if echo $2 | grep -q no; then
  if [ $[6+$1] -gt 7 ]; then
    echo $[4+$1]
  else
    echo $[6+$1]
  fi
elif [ $[6+$1] -gt 7 ]; then
  echo $[2+$1]
else
  echo $[4+$1]
fi

udev rules:

SUBSYSTEMS=="usb" , KERNELS=="?-?.?:?.0" , DRIVERS=="pl2303" , PROGRAM="/opt/sagetv/server/ttyUSB_converter %n hub", SYMLINK+="ttyS%c"
SUBSYSTEMS=="usb" , KERNELS=="?-?:?.0" , DRIVERS=="pl2303" , PROGRAM="/opt/sagetv/server/ttyUSB_converter %n nohub", SYMLINK+="ttyS%c"

Because the load order differs between the chipsets on reboots I had to make the above changes. I also wanted to keep it in 1 script.

B