Very weird problem with dc driver

[David Malone]

> >>Dec 25 00:32:58 xevious /kernel: dc0: TX underrun -- increasing TX 
> >>threshold

> > In general, you don't need to worry about these, they are just the driver
> > adjusting itself to the speed of your card/motherboard. You may see a few
> > of them when the machine is first busy after boot, and then they should
> > probably stop.

> I have a machine running 4.9 and using the dc driver (Netgear FA310TX) 
> that gets lots of these messages. For the most part they happen when the 
> network cable is unplugged, but I also get a number of them randomly. 
> They're not entirely harmless either since the umass driver seems to be 
> affected. If one of the messages pops up while transferring to/from a 
> usb drive the transfer stalls in poll (according to top) and any 
> subsequent attempt to access (ls,cd, etc) either disk involved in the 
> transfer also gets locked in the poll state.

While it's possible that the TX underrun is somehow causing your
USB subsystem to stall, it seems more likely that either the USB
subsystem is stalling your NIC or that something else is stalling
both of them.

> Google found a few other threads but I don't feel like listing them.

Most of the threads that you posted say roughly what I's said,
"don't worry about them". One did mention that there may be hardware
problems with the Netgear card that you mention. However, the section
of the driver man page quoted suggests that the driver contains
work-arounds for these problems.

	David.