[LAD] jackd and usb hub

Luis Garrido luisgarrido at users.sourceforge.net
Fri Oct 15 09:21:03 UTC 2010

On Fri, Oct 15, 2010 at 8:44 AM, Clemens Ladisch <clemens at ladisch.de> wrote:
> hub) so that the full-speed (USB 1.x) UHCI/OHCI controller driver is
> used, or unload the ehci_hcd module so that the hub is forced to run at
> USB 1.x speed.  (The rate-matching hub in the Intel P/Q/H 55/57 chipsets

There's nothing like knowing fully what one's talking about. Very
informative, Clemens, as usual. Thanks a lot!

One caveat, though: ehci_hcd is built into the stock kernel both in
Fedora Core 12 and Ubuntu Lucid. So, if you want to disable USB 2.0
for some of your devices you'll have to unbind them (and from the
darkness free them ;-) .)

# cd /sys/bus/pci/drivers/ehci_hcd/
# echo -n 0000:03:00.2 > unbind

Ta-dah! jackd through a 1.x-fied USB 2.0 hub.



OTPS: So what's with this worrying recurring fad of compiling modules
into the kernel? Ubuntu did it with acpi-cpufreq too and screwed with
the possibility of using linux-phc to undervolt your CPU and quieting
down your fans. :-(

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