Date: Wed, 31 Mar 2004 19:58:14 +0200 From: Bernd Walter <ticso@cicely12.cicely.de> To: "M. Warner Losh" <imp@bsdimp.com> Cc: ticso@cicely.de Subject: Re: usbd config file parse behaviour Message-ID: <20040331175813.GA44049@cicely12.cicely.de> In-Reply-To: <20040331.093211.102577197.imp@bsdimp.com> References: <20040330.014632.132641792.imp@bsdimp.com> <20040330090601.GE32646@cicely12.cicely.de> <39883.134.148.20.33.1080706267.squirrel@134.148.20.33> <20040331.093211.102577197.imp@bsdimp.com>
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On Wed, Mar 31, 2004 at 09:32:11AM -0700, M. Warner Losh wrote: > : I agree that it's bad to yank a device from under ugen automatically and > : reattach it to a better match. > > I think it is good. Really. However, ugen should mark the device > busy when it is opened, and mark it as unbusy as closed and the > reprobe shouldn't happen if the device is busy. Otherwise, there's no > harm. ugen2 goes away, who cares. ugen0, ugen1, and ugen3 would > still be there. However, if a device is in use, the probe routines of > other divices may interfere. ugen has a busy flag in his softc. > Part of the problem is we can't tell a driver 'detach if you aren't > busy' vs 'detach now, your hardware is gone or about to be gone'. > Maybe we should fix that at the same time. There's also a desire from > the hot-plug bus people to have a 'quiesce' the device, which is > similar to the current suspend method, but with different semantics > (quiesce means stop using the hardware, while suspend says put the > hardware to sleep). Yes - a generic way would be best. And of course reprobe is not everything. In the USB as well as in the hot-plug PCI case there is a need for functions to disable/enable ports/slots manually - I think that fits with what you mean by 'quiesce'? If someone with more knowledge about the generic part could implement this then I could do the USB specific part. > : How about adding a new ioctl on /dev/usb, eg USB_REPROBE to reset a device > : if a better match exists? > > I don't want this to be USB specific. usb has enough kludgy hacks. > That's why we're in this mess. If we do something like this, then we > should do it for all devices on all busses. > > : Could tack an option on to usbdevs to call it on requested devices. > > Absolutely not. We want uniform behavior. It would be a nightmare to > manage a huge table in the kernel with exceptions. usbdevs is not the right tool for this kind of functionality anyway. devinfo -v with the usb devd support is already more generic then usbdevs. Meating up the informations is simple once there is no static size limit. A userland tool for reprobe should be named more like devctl and be able to operate on the whole device tree. -- B.Walter BWCT http://www.bwct.de ticso@bwct.de info@bwct.de
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