Continuing an old thread on additional USB ports, and leaving the
arguments PCI card vs hub out.
The 4-port USB 2.0 PCI card from TasTech ($20) has a Via VT6202 chip on
it and presents itself as 3 PCI devices (which is standard for these
cards).
00:0c.0 USB Controller: VIA Technologies, Inc. USB (rev 50)
00:0c.1 USB Controller: VIA Technologies, Inc. USB (rev 50)
00:0c.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 51)
USB 1.1 devices work fine, 2.0 devices do not at least under SuSE 8.2
kernel 2.4.20. Symptoms are I/O hangs with difficulty killing the
process, and possibly interference with the IDE disks (it caused at
least one disk error and a RAID resync for me).
The card needs 3 interrupts and they get spread evenly around by the
BIOS ("no pnp OS" setting) and shared with other devices. Turning USB
interrupts off in the BIOS deadens USB totally. The mobo USB can't be
disabled separately. The disk problem might well be related to
interrupt problems but I don't see how I can assign them differently.
Assigning interrupts to PCI slots in the BIOS has no effect.
Indication is that the ehci-hcd module is flaky unless one has very
recent kernel versions. Other USB chips(ets) don't seem to cause as
many problems.
A Knoppix 3.4 doesn't load the ehci-hcd module automatically and
doesn't run attached devices as 2.0 (a bit of a laugh really). Manually
loading module ehci-hcd doesn't cause the USB 2.0 device to be attached
to the 2.0 bus but does noticably increase at least read transfer
rates. Not satisfactory.
That's the state so far. The problems are likely to be similar with
mobo-integrated USB 2.0.
Volker
--
Volker Kuhlmann is possibly list0570 with the domain in header
http://volker.dnsalias.net/ Please do not CC list postings to me.
