On Mon, Jun 08, 2009 at 07:47:06PM -0400, Alan Stern wrote: > On Mon, 8 Jun 2009, Matthew Garrett wrote: > > > If I indicate it needs a reset-resume then it doesn't seem to actually > > be reset unless I add the needs_binding option in the reset_resume > > callback, which strikes me as being absolutely the wrong thing to do. > > It sure is. > > I don't understand why you don't get a reset. In driver.c, > usb_resume_device() includes this code: > > if (udev->quirks & USB_QUIRK_RESET_RESUME) > udev->reset_resume = 1; > > That's why setting the quirk bit in udev should be all you need to do. The needs_binding option only seems to be set in the case where USB_QUIRK_RESET_RESUME is present but there's no reset_resume callback in the driver? I don't have enough experience of the USB core to know what that's actually doing. > > When system suspend takes place it reboots itself and appears as a > > different USB ID, so there's no hope of restoring state. > > In theory, the behavior during a system suspend should be the same as > the behavior during an autosuspend. Which means that after an > autoresume, the device should show up with a different USB ID and so > the reset would fail. But that's probably not what's really happening. The card comes up in a dumb state and then gets fed 16MB worth of armel ELF object which causes it to reboot into a more useful form. It stays in that state until the power plane is entirely cut, which happens in system suspend but not in autosuspend. > > It's possible that this is unnecessary in the first place and I'm > > working around some other problem. With vanilla code, if I echo > > "suspended" to power/level and then echo "on" to it, the device works. > > If I echo "auto" to it and leave it to suspend, then it stops working > > until I switch it back to "on", even if I don't explicitly reset it. I'm > > not sure why this makes a difference. > > It should not make any difference. Can you provide dmesg output with > CONFIG_USB_DEBUG enabled, together with a usbmon trace? You might also > want to #define VERBOSE_DEBUG at the start of drivers.c (before the > #include lines). I'll grab those shortly. -- Matthew Garrett | mjg59@xxxxxxxxxxxxx -- 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
