Hi Hans, 2013-09-28 Hans de Goede <hdegoede@xxxxxxxxxx>: > Many btusb devices have 2 modes, a hid mode and a bluetooth hci mode. These > devices default to hid mode for BIOS use. This means that after having been > reset they will revert to HID mode, and are no longer usable as a HCI. > > Therefor it is a very bad idea to just blindly make reset_resume point to > the regular resume handler. Note that the btusb driver has no clue how to > switch these devices from hid to hci mode, this is done in userspace through > udev rules, so the proper way to deal with this is to not have a reset-resume > handler and instead let the usb-system re-enumerate the device, and re-run > the udev rules. > > I must also note, that the commit message for the commit causing this > problem has a very weak motivation for the change: > > "Add missing reset_resume dev_pm_ops. Missing reset_resume results in the > following message after power management device test. This change sets > reset_resume to btusb_resume(). > > [ 2506.936134] btusb 1-1.5:1.0: no reset_resume for driver btusb? > [ 2506.936137] btusb 1-1.5:1.1: no reset_resume for driver btusb?" > > Making a change solely to silence a warning while also changing important > behavior (normal resume handling versus re-enumeration) requires a commit > message with a proper explanation why it is safe to do so, which clearly lacks > here, and unsurprisingly it turns out to not be safe to make this change. > > Reverting the commit in question fixes bt no longer working on my Dell > E6430 after a suspend/resume, and I believe it likely also fixes the > following bugs: > https://bugzilla.redhat.com/show_bug.cgi?id=988481 > https://bugzilla.redhat.com/show_bug.cgi?id=1010649 > https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1213239 > > This reverts commit 502f769662978a2fe99d0caed5e53e3006107381. > > Cc: Shuah Khan <shuah.kh@xxxxxxxxxxx> > Cc: Gustavo Padovan <gustavo.padovan@xxxxxxxxxxxxxxx> > Cc: stable@xxxxxxxxxxxxxxx > Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx> > --- > drivers/bluetooth/btusb.c | 1 - > 1 file changed, 1 deletion(-) Patch has been applied to bluetooth.git. Thanks. Gustavo -- 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
