Messages in this thread | | | Date | Sun, 14 Jan 2007 19:47:12 +0000 (GMT) | From | icxcnika@mar ... | Subject | Re: [linux-usb-devel] 2.6.20-rc4: usb somehow broken |
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On Sun, 14 Jan 2007, Alan Stern wrote:
> On Sun, 14 Jan 2007, Prakash Punnoor wrote: > >> Am Sonntag 14 Januar 2007 10:28 schrieb Oliver Neukum: >>> Am Sonntag, 14. Januar 2007 10:08 schrieb Prakash Punnoor: >>>> Am Donnerstag 11 Januar 2007 18:28 schrieb Oliver Neukum: >>>>> Am Donnerstag, 11. Januar 2007 18:20 schrieb Prakash Punnoor: >>>>>> Hi, >>>>>> >>>>>> I can't scan anymore. :-( I don't know which rc kernel introduced it, >>>>>> but this are the messages I get (w/o touching the device/usb cable >>>>>> except pluggin it in for the first time): >>>>>> >>>>>> usb 1-1.2: new full speed USB device using ehci_hcd and address 4 >>>>>> ehci_hcd 0000:00:0b.1: qh ffff81007bc6c280 (#00) state 4 >>>>>> usb 1-1.2: configuration #1 chosen from 1 choice >>>>>> usb 1-1.2: USB disconnect, address 4 >>>>>> usb 1-1.2: new full speed USB device using ehci_hcd and address 5 >>>>>> usb 1-1.2: configuration #1 chosen from 1 choice >>>>>> usb 1-1.2: USB disconnect, address 5 >>>>>> usb 1-1.2: new full speed USB device using ehci_hcd and address 6 >>>>>> usb 1-1.2: configuration #1 chosen from 1 choice >>>>>> usb 1-1.2: USB disconnect, address 6 >>>>>> usb 1-1.2: new full speed USB device using ehci_hcd and address 7 >>>>>> usb 1-1.2: configuration #1 chosen from 1 choice >>>>>> usb 1-1.2: USB disconnect, address 7 >>>>>> usb 1-1.2: new full speed USB device using ehci_hcd and address 8 >>>>>> usb 1-1.2: configuration #1 chosen from 1 choice >>> >>> [..] >>> >>>> Hi, I did more tests and I was wrong about "broken". It seems more a >>>> time-out problem, ie if I try to use sane again in short intervalls, I >>>> will get my device working. The cause seems CONFIG_USB_SUSPEND=y. With >>>> 2.6.20-rc5 the >>> >>> Have you confirmed that by using a kernel without CONFIG_USB_SUSPEND ? >> >> Yes. I compiled the modules with various settings, reloaded the modules and >> above option made the difference. I also don't get the disconnect mesages, as >> well, w/o USB_SUSPEND. > > Judging from the log, it looks like the scanner cannot handle being > suspended. (BTW this is in violation of the USB specification -- all > devices must be able to suspend and resume.) > > When the scanner is not in use, the system automatically suspends it after > two seconds. When you use sane the scanner is resumed, but it then > disconnects itself and reconnects. Sane is left trying to control the > disconnected device instance, so of course it fails. > > I'm beginning to think that we need some way to deal with devices that > cannot recover from a suspend. Several examples have cropped up. > Unfortunately, I can't think of anything better than a blacklist, which is > not very satisfactory. > > Can anyone suggest another approach? > > Alan Stern
Just a thought, you could use both a blacklist approach, and a module paramater, or something in sysfs, to allow specifying devices that won't be suspend and resume compatible.
William Heimbigner icxcnika@mar.tar.cc - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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