On Wed, 27 Apr 2005, David Brownell wrote: > On Wednesday 27 April 2005 2:32 pm, Alan Stern wrote: > > > > That's not in question. The issue is: Out of all the drivers floating > > around, which one should decide when a particular device can be suspended > > for lack of activity? > > Erm, not just _one_ can do it. Certainly any interface's driver can know > that it's now idle; for example, if a network interface is down, that > particular interface can be suspended (then resumed later as needed).
Yes indeed. This is what I had in mind, and it's the way my hub autosuspend patch worked -- the hub driver knew when the hub was idle. > But usbcore has two obvious places to put such logic. Basically, the > two modes of "usb_device" ... one for normal devices (with one or > more interfaces, bound to drivers), and the other for hubs (managing > ports or child devices, however you look at it). Sorry, I don't understand this paragraph. Are you drawing a distinction between the hub driver autosuspending a hub and some other device (or interface) driver autosuspending its device? If so, I don't see why such a distinction needs to be made. If not, then where are the "two obvious places"? > > I do have an old patch somewhere for adding hub autosuspend. It never > > went very far, partly because of the ongoing changes in the PM core and > > partly because OHCI didn't like it. And UHCI's root hub support wasn't in > > good enough shape at the time to allow autosuspend, although now it should > > be okay. The patch did work when suspending external hubs attached to a > > UHCI controller. > > I remember that. It's the right direction, but the patch was just > a bit early ... :) Do you think the time is more ripe just now? :-) Alan Stern ------------------------------------------------------- SF.Net email is sponsored by: Tell us your software development plans! Take this survey and enter to win a one-year sub to SourceForge.net Plus IDC's 2005 look-ahead and a copy of this survey Click here to start! http://www.idcswdc.com/cgi-bin/survey?id=105hix _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
