On Tue, Nov 19, 2013 at 02:53:22PM +0000, Cortes, Alexis wrote: > Hi Sarah, > > Sorry for my delayed response, I just saw your e-mail (it got filtered somehow). About your question: actually I'm not sure, I'll have to check that to confirm it. I'll get back to you with an answer as soon as I have it. Ping, Alexis: any info on this question? Sarah Sharp > -----Original Message----- > From: Sarah Sharp [mailto:sarah.a.sharp@xxxxxxxxxxxxxxx] > Sent: Thursday, November 14, 2013 5:31 PM > To: Alan Stern > Cc: Julius Werner; Greg Kroah-Hartman; LKML; linux-usb@xxxxxxxxxxxxxxx; Benson Leung; Vincent Palatin; Cortes, Alexis > Subject: Re: [PATCH] usb: hub: Use correct reset for wedged USB3 devices that are NOTATTACHED > > On Thu, Nov 07, 2013 at 10:32:33AM -0500, Alan Stern wrote: > > On Wed, 6 Nov 2013, Julius Werner wrote: > > > > > > What if the device is in USB_STATE_SUSPENDED? > > > > > > I'm not sure that is possible at that point in hub_events(), I don't > > > know of a way that could lead to this situation. I could still add > > > the check just to be sure if you want it, though. > > > > I don't know either. But Sarah has said that ports can spontaneously > > go into Compliance Mode for no apparent reason. If that can happen, > > maybe it can happen while the port is in U3 and the device is > > suspended. In such cases, though, you'd need to do a reset-resume > > rather than a simple reset. > > Looking at commits c3897aa5386faba77e5bbdf94902a1658d3a5b11 and 71c731a296f1b08a3724bd1b514b64f1bda87a23, it seems that the TI host controllers' ports can go into compliance mode only when a device is inserted. Once the device is link trained by the redriver, the port shouldn't go into compliance mode. So we should never see compliance mode on a port with an attached USB device in suspend. > > Alex, can you confirm that the TI host's port won't go into compliance mode while a connected device is suspended? > > > > > Not at all. If a device is unplugged, its state changes to > > > > NOTATTACHED before the driver is unbound. During that time, the > > > > driver will see all its URBs failing, so it may very well try to reset the device. > > > > (For example, usbhid behaves like this.) That isn't a bug. > > > > > > Oh, okay, I wasn't quite sure how that plays together. Would you > > > think it's still valuable to print it out (maybe as dev_info() > > > instead of > > > dev_warn()) instead of just silently ignoring the reset request? It > > > would have certainly been useful for me to find this problem faster, > > > but I can take it out again if you think it would result in too much > > > noise. > > > > I think keeping dev_dbg() is best. If you're searching for the > > solution to a problem, you should have debugging enabled and so you > > ought to see the message. > > > > Alan Stern > > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
