On Thu, Dec 22, 2005 at 03:51:51PM -0800, Steve Calfee wrote: > On Thu, 2005-12-22 at 15:31 -0800, Greg KH wrote: > > On Thu, Dec 22, 2005 at 08:12:02PM +0000, James Courtier-Dutton wrote: > > > Randy.Dunlap wrote: > > > >> > > > >>Load ehci-hcd OR ohci-hcd, but not both at the same time. > > > > > > > > > > > >What's the reasoning for that? > > > > > > > >EHCI needs a "companion" controller and driver (like > > > >UHCI or OHCI) for non-high-speed devices. > > > > > > > > > > Since when? > > > > Since always, read the USB 2.0 spec? :) > > > > Actually the usb.org spec does not address controller hardware. The > Intel EHCI spec is the one that talked about "companion controllers".
Oops, you are right, sorry about that. > It always seemed like an incredible kludge to have 1 to n companions > just to handle full speed and low speed. The Arc/Transdimensional core > handles all 3 speeds in just its "enhanced" EHCI hardware. I imagine > that when Intel was doing the prototype EHCI chip they either had a bug > in FS/LS or ran out of time and just tacked on their existing UHCI > controller hardware to get it out the door. Based on the timeline for the USB 2.0 spec, and the huge mess that is involved in a USB 2.0 hub chip, I bet you are correct in that they ran out of time. thanks, greg k-h ------------------------------------------------------- This SF.net email is sponsored by: Splunk Inc. Do you grep through log files for problems? Stop! Download the new AJAX search engine that makes searching your log files as easy as surfing the web. DOWNLOAD SPLUNK! http://ads.osdn.com/?ad_id=7637&alloc_id=16865&op=click _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
