Re: Anyone using a StarTech PCI420USB card? (USB 2.0, 4-port, PCI card)

[Risto Suominen <risto.suominen@gmail.com>]

Hi Rick,

ehci-hcd can take three parameters:

log2_irq_thresh (0-6): log2 IRQ latency, 1-64 microframes
park (1-3): park setting; 1-3 back-to-back async packets
ignore_oc (0-1): ignore bogus hardware overcurrent indications

I don't really know what they mean, and I doubt they would help here,
but it may be worth a try. You could create a new file,
/etc/modprobe.d/ehci-hcd.conf:

options ehci-hcd log2_irq_thresh=6 park=3 ignore_oc=1

Then execute:

modprobe -r ehci-hcd
modprobe ehci-hcd

It can hardly get worse.

uhci-hcd is always loaded: it provides USB 1.1 connectivity, i.e.
speeds up to 12 Mbit/s. ehci-hcd provides USB 2.0, speed 480 Mbit/s.
So it probably doesn't make sense to remove it permanently, but just
for test's sake:

modprobe -r ehci-hcd

And permanently (/etc/modprobe.d/ehci-hcd.conf):

blacklist ehci-hcd

Now the device should be detected as full speed instead of high speed.
Yes, full speed is much lower in this case.

Risto