Re: Request for information

David KE6UPI

Hello Steve, I'm running an old Dell Optiplex 960 i3 (3rd Gen) 4Gb ram. 

Should the latency_timer be set to 16 or 1?


Thanks, David

"Laws that forbid the carrying of arms...disarm only those who are neither inclined nor determined to commit crimes. Such laws make things worse for the assaulted and better for the assailants; they serve rather to encourage than prevent homicides, for an unarmed man may be attacked with greater confidence than an armed one."
Thomas Jefferson

On Wed, Jan 17, 2018 at 6:14 AM, Steve N4IRS <szingman@...> 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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