Messages in this thread |  | | Date | Thu, 8 Nov 2001 17:34:04 -0500 | From | Johannes Erdfelt <> | Subject | Re: Big USB speed difference when compiled as module (was Re: speed difference between using hard-linked and modular drives?) |
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On Thu, Nov 08, 2001, Tim Pepper <tpepper@vato.org> wrote: > On Thu 08 Nov at 17:01:24 +0100 roy@karlsbakk.net done said: > > > > Are there any speed difference between hard-linked device drivers and > > their modular counterparts? > > I've been wondering this as well. I've got a curious situation: With usbcore > and the uhci driver compiled into the kernel I can initiate transfers to a usb > device I have (Creative Nomad Jukebox) at what I'm eyeballing to be near the > 12Mbps USB speed. These tranfers always fail. With both drivers compiled as > modules the transfers are over an order of magnitude slower, not even > appearing to reach the 1.5Mbps USB speed, but they succeed. I haven't had a > chance to try to figure out what's going on for sure. > > It's been a little while since I was playing with this but I believe I saw > the same thing with the usb-uhci driver as well but it didn't seem to like > talking to the Nomad regardless of it being compiled as a module or not. > This was with the 2.4.13 kernel. I can provide more details upon request.
This absolutely should not be the result of compiling into the kernel. It's most likely a bug in the HC which just happened to show up with modules.
> BTW: is there a way to do USB sniffing in software in linux? I'd imagine it's > possible, but just can't find anything that does...
Not in Linux yet.
JE
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