13 May
2012
13 May
'12
10:40 p.m.
On Sun, May 13, 2012 at 4:06 PM, Robin Gareus <robin(a)gareus.org> wrote:
Any hints on how to address this issue, then? If I
understand correctly,
new USB2-class-compliant devices are not an issue, but on modern
machines with only EHCI, USB1-class-compliant devices may or may not
work... right?
The primary problem with EHCI is only bandwidth allocation; it's
inefficient. I'm unaware of any timing problems. That's not to say
they don't exist, I just haven't run into them myself.
Poor bandwidth efficiency aside, I usually see ~ the same latency and
timing behavior on UHCi and EHCI with a TT.
Would forward porting your schedulers be an option?
Has anything of this
been merged into recent kernels?
I'm unlikely to do this unless I need it myself, sorry :-(. Not
enough time, too much to do. And the kernel devs are absolutely right
that replacing a working but inefficient driver with a brand new one
that is faster but will require long-term testing is not something to
be done lightly.
Maybe you can do play some tricks on the EHCI
controller/scheduler: add
an old USB1.1 hub in between the soundcard and the PC... but that's just
a shot in the dark.
You'll still be going through the translator in the root hub.
Monty