Re: Request for information

G7RPG - Peter Kendall


My asl box running Analog_Bridge is Debain 8.9 VM on ESX 6.5 (i5 3570K) the value of latency_timer is 1

[    5.343999] usbcore: registered new interface driver ftdi_sio
[    5.344007] usbserial: USB Serial support registered for FTDI USB Serial Device
[    5.344032] ftdi_sio 1-2.2:1.0: FTDI USB Serial Device converter detected
[    5.344049] usb 1-2.2: Detected FT-X
[    5.344050] usb 1-2.2: Number of endpoints 2
[    5.344052] usb 1-2.2: Endpoint 1 MaxPacketSize 64
[    5.344053] usb 1-2.2: Endpoint 2 MaxPacketSize 64
[    5.344054] usb 1-2.2: Setting MaxPacketSize 64


On 17/01/18 14:14, Steve N4IRS wrote:

We have been working on the next revision of Analog_Bridge. Along with adding features and refining settings, we are trying to squash bugs. While testing the NWDigital DV300u (ThumbDV) we encountered a problem with data transfer . Some of the packets were not being processed in the required window. The NWD DV3000u uses a FTDI chip to communicate with the host computer. Under Linux, or at least Debian the driver is the FTDI serial. On the machine under test, a older Dell 2950 with more then enough horsepower and no history of issues with USB, we were not getting data in a timely manner. There is a value that can be adjusted to resolve this. /sys/bus/usb-serial/devices/ttyUSB0/latency_timer. The default looks to be 16. The 2950 was set at 16. So far so good. Well, I have a machine running a full time DMR <---> D-Star bridge using two of the DV3000u. When I checked the latency_timer, it was set to 1. Huh? I know I did not change it.

I am asking everybody that is using a DV3000 and a FTDI chip to test with the device plugged in. As root: cat /sys/bus/usb-serial/devices/ttyUSB0/latency_timer. Please report the result here. We have multiple ways to set this to what we want, but for now, All I want to know is what hardware / software you are running and the value.

Thanks, Steve


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