Date: Mon, 24 May 2004 09:00:38 +0900 From: Rob <stopspam@users.sourceforge.net> To: freebsd-stable@freebsd.org, iedowse@maths.tcd.ie Subject: Re: USB patch for better bus_dma and detachment support Message-ID: <40B13B26.10201@users.sourceforge.net> In-Reply-To: <200405232109.aa46210@salmon.maths.tcd.ie> References: <200405232109.aa46210@salmon.maths.tcd.ie>
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Ian Dowse wrote: > In case anybody is interested in testing or helping with this, > there's a patch at > > http://people.freebsd.org/~iedowse/usb.diff > > that attempts to begin addressing a number of problems with our > current USB code: > > o All data buffers were allocated using bus_dma as physically > contiguous memory. All transfers involve a memory copy to/from > these contiguous buffers, and the contiguous memory is never > freed. Use of these buffers is also inefficient, so low-memory > systems tend to quickly run out of usable physical memory. > > o USB host controllers cannot be detached, so for example, unplugging > a cardbus USB device will cause a crash. > > Neither of these issues is completely solved by the patch, but most > I/O now avoids the need for contiguous buffers by using bus_dmamap_load() > on the virtual buffer, and the system seems to survive the removal > of a cardbus OHCI/EHCI controller, though memory is probably leaked. Can I apply this patch safely to STABLE as well? If not, then, if you make a patch for STABLE, I would test it right away! My umass storage USB toy, crashes the system when I umount it. I blamed the USB chipset (VIA 83C572 USB controller), but am still not sure, since I did not get much response from the STABLE mailing list. It would be great if your patch would solve the crash! Regards, Rob.
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