On Wed, May 21, 2014 at 10:29:09AM -0700, Dan Williams wrote: > On Tue, May 20, 2014 at 11:31 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > > On Tue, May 20, 2014 at 11:21:03PM -0700, Dan Williams wrote: > >> On Tue, May 20, 2014 at 5:27 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote: > >> >> Greg, > >> >> > >> >> Sorry, I don't think it is fair to users to force them to re-compile > >> >> their kernel to get their device to work. > >> > > >> > I totally agree. > >> > > >> >> Granted, I'm new to USB > >> >> development, but the rate of reports of endpoint devices that mess up > >> >> and require quirks in the hcd-driver or usb-core seems un-ending to > >> >> me. So, I don't think it is fair to expect that the tide of quirky > >> >> devices will be stemmed in any reasonable amount of time. Having a > >> >> "works with noxhci_port_switch" report from users is good data (hmm, I > >> >> think a printk to tell users to file a report upstream if the option > >> >> resolves their issue is needed). > >> > > >> > How about just adding a debugfs file instead? That way, once you fix > >> > this, we can then remove it and no one will care. > >> > >> The only thing stopping me from saying "deal." is that this darn > >> things is presently a pci quirk. So it happens well before the user > >> has a chance to manually override it with a debugfs file. > > > > Then have the debugfs file disconnect the device and reconnect it. > > We also need to reload the ehci hcd driver since it needs to know its > port count at load time as well. Which is more violent and error > prone than I think we want. Why is that a problem? > >> Let me look into delaying the quirk until the driver loads, because > >> ideally the right interface for this is "blacklist xhci_hcd" in > >> /etc/modprobe.conf. > > > > Which really doesn't work for systems / distros that build the driver > > into the kernel. > > True. I'm back to a kernel command line option as the only viable way > forward, but let me try to wordsmith the description to make clear > when to use this workaround and the obligation to report upstream when > this workaround works so we can queue up the fix for xhci. No, I really don't want a command line option if at all possible as you will have to support it for forever. greg k-h -- 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
