On Mon, 4 Jun 2007, Michael Hanselmann wrote: > On Sat, Jun 02, 2007 at 10:49:44AM -0400, Alan Stern wrote: > > Then later on, when the hub driver is resumed it will see the flag and > > disconnect all the devices below the root hub. > > > For instance, you could force ohci-hcd to report connect-change events > > on all the ports. Perhaps it does something like that anyway, in which > > case you wouldn't have to worry about it. > > After studying the code for two evenings, I'm quite sure it does that > already. > > A comment in ohci-hcd.c:ohci_restart reads: > /* mark any devices gone, so they do nothing till khubd disconnects. > * recycle any "live" eds/tds (and urbs) right away. > * later, khubd disconnect processing will recycle the other state, > * (either as disconnect/reconnect, or maybe someday as a reset). > */
Don't believe everything you read in comments. That one is very out of date. It should be removed. > usb_root_hub_lost_power marks the ports as gone, khubd will disconnect them. Wrong. usb_root_hub_lost_power does _not_ mark the ports as gone, and it does _not_ tell khubd to disconnect them. (Depending on which version of the kernel you are looking at -- I'm referring to the latest development kernel including the gregkh-all patch set. Earlier versions did behave the way you describe.) > After restarting the chip, khubd will cause them to be detected again. > > This is also what I can watch in the logs: > ohci_hcd 0001:10:15.1: OHCI Unrecoverable Error, scheduling NEC chip restart > usb usb2: root hub lost power or was reset > usb 2-2: USB disconnect, address 2 > input: appletouch disconnected > usb 2-2: new full speed USB device using ohci_hcd and address 3 > usb 2-2: configuration #1 chosen from 1 choice > input: Apple Computer Apple Internal Keyboard / Trackpad as > /class/input/input16 on usb-0001:10:15.1-2 > input: appletouch as /class/input/input17 > input: Apple Computer Apple Internal Keyboard / Trackpad as > /class/input/input18 on usb-0001:10:15.1-2 > > (Actually, I added some code to trigger the error handling code, reliably > reproducing it otherwise is impossible.) So the system is behaving the way you want, but not for the reason you think. I bet you could remove the call to usb_root_hub_lost_power() entirely and it wouldn't make any difference at all. Alan stern - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
