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Re: [Owfs-developers] Issue with LinkUSB dropping
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From: Stefano M. <mo...@ic...> - 2014-06-06 07:21:04
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the LinkUSB is a serial over USB adapter: can you rule out USB problems?
I have a LinkUSB connected to a very old server running Linux and sometimes the device gets "disconnected":
[ 1.808165] usb 1-5.2: new full-speed USB device number 4 using ehci_hcd
[ 1.906558] usb 1-5.2: New USB device found, idVendor=0403, idProduct=6001
[ 1.906563] usb 1-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[ 1.906566] usb 1-5.2: Product: FT232R USB UART
[ 1.906569] usb 1-5.2: Manufacturer: FTDI
[ 1.906572] usb 1-5.2: SerialNumber: XXXXXXXX
[ 6.601905] usb 1-5.2: Detected FT232RL
[ 6.601908] usb 1-5.2: Number of endpoints 2
[ 6.601912] usb 1-5.2: Endpoint 1 MaxPacketSize 64
[ 6.601915] usb 1-5.2: Endpoint 2 MaxPacketSize 64
[ 6.601918] usb 1-5.2: Setting MaxPacketSize 64
[ 6.602420] usb 1-5.2: FTDI USB Serial Device converter now attached to ttyUSB0
...
[529298.815921] usb 1-5.2: USB disconnect, device number 4
[529299.340167] usb 1-5.2: new full-speed USB device number 5 using ehci_hcd
[529299.438420] usb 1-5.2: New USB device found, idVendor=0403, idProduct=6001
[529299.438425] usb 1-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[529299.438429] usb 1-5.2: Product: FT232R USB UART
[529299.438432] usb 1-5.2: Manufacturer: FTDI
[529299.438435] usb 1-5.2: SerialNumber: XXXXXXXX
[529299.441024] usb 1-5.2: Detected FT232RL
[529299.441027] usb 1-5.2: Number of endpoints 2
[529299.441030] usb 1-5.2: Endpoint 1 MaxPacketSize 64
[529299.441034] usb 1-5.2: Endpoint 2 MaxPacketSize 64
[529299.441036] usb 1-5.2: Setting MaxPacketSize 64
[529299.441403] usb 1-5.2: FTDI USB Serial Device converter now attached to ttyUSB1
...
[1016813.881513] usb 1-5.2: USB disconnect, device number 5
[1016814.412250] usb 1-5.2: new full-speed USB device number 6 using ehci_hcd
[1016814.510375] usb 1-5.2: New USB device found, idVendor=0403, idProduct=6001
[1016814.510380] usb 1-5.2: New USB device strings: Mfr=1, Product=2, SerialNumber=3
[1016814.510384] usb 1-5.2: Product: FT232R USB UART
[1016814.510387] usb 1-5.2: Manufacturer: FTDI
[1016814.510390] usb 1-5.2: SerialNumber: XXXXXXXX
[1016814.513109] usb 1-5.2: Detected FT232RL
[1016814.513113] usb 1-5.2: Number of endpoints 2
[1016814.513116] usb 1-5.2: Endpoint 1 MaxPacketSize 64
[1016814.513120] usb 1-5.2: Endpoint 2 MaxPacketSize 64
[1016814.513123] usb 1-5.2: Setting MaxPacketSize 64
[1016814.513478] usb 1-5.2: FTDI USB Serial Device converter now attached to ttyUSB0
So here you see that once a week or so my linkUSB is disconnected and "rediscovered", which means that I have the linkUSB bouncing between /dev/ttyUSB0 and /dev/ttyUSB1. I have no idea who is responsible of this behaviour (the server USB adapter? the linkUSB? the Linux kernel?)
I solved the problem with a custom udev rule, which creates a /dev/linkUSB0 symlink to the current /dev/ttyUSBx device.
SUBSYSTEM=="tty", \
ATTRS{product}=="FT232R USB UART", ATTRS{serial}=="XXXXXXXX", \
SYMLINK+="linkUSB0", GROUP="owfs"
where of course you have to substitute XXXXXXXX with the actual serial number. BTW I also set the group to "owfs" instead of "dialout" since I do not run owserver as root but as a user belonging to the group, you guess, "owfs".
S.
On 05 Jun 2014, at 13:52, Johan Ström <jo...@st...> wrote:
> Hi,
>
> I got a LinkUSB as a master for my 1-wire net, around 80m with 30 devices.
> The bus is scanned every minute and temperature sensors polled (most of
> the devices). Around 3 times a second I try to scan the alarm dir for
> alarms (DS2406's), and possibly handle these.
>
> Normally this works perfectly fine, and has done so for a few years. No
> re-reads or CRC errors according to the counters.
> However, a few times during these years, the whole network has become
> inaccessible, and the only way to get it back into working shape has
> been to unplug the LinkUSB from both the 1w-network (DQ+DGND), and the
> USB port.
> Once doing this, it all comes back up immediately, and all devices work
> fine.
>
> If I recall correct I have also pulled the external 5V feed to the
> devices too, but just disconnecting the 1w-network from the LinkUSB, and
> disconnecting the 5V feed has NOT been enough, the USB port must be
> disconnected as well. Restart of owserver does not help.
>
>
> Anyone else with similar experiences, or ideas on what might be causing
> this or how to work around it? Hard to debug since I cannot really
> reproduce it at will..
>
> Thanks
> Johan
>
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