On Mon, 26 Dec 2005, Bodo Eggert wrote: > On Mon, 26 Dec 2005, Lee Revell wrote: > > On Mon, 2005-12-26 at 11:25 +0100, Bodo Eggert wrote: > > > > Document the current status of CONFIG_USB_BANDWITH implementation. > > > > Since most systems use uhci-hcd and/or ehci-hcd maybe we should just > > mark it BROKEN? Or EXPERIMENTAL? > > It is EXPERIMENTAL, but the current documentation sounds like "YOU REALLY > WANT THIS !!!1", and I /guess/ that would be true for ohci-hcd users.
CONFIG_USB_BANDWIDTH isn't _really_ needed. What it does (or rather, what it would do if it worked properly) is prevent the kernel from overcommitting on USB bandwidth. If it's not set, the kernel will allow drivers to reserve more bandwidth than is actually available, with the result that data transfers will fail. If it is set, drivers will not be allowed to reserve too much bandwidth, so again the I/O will fail (but at an earlier stage). Provided drivers never try to overcommit, it doesn't matter whether the option is set or not. And note that a single driver is most unlikely to overcommit on bandwidth; the problems arise when you have more than one driver all trying to use a lot of bandwidth at the same time. Alan Stern ------------------------------------------------------- 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
