On Tue, 21 Jan 2020, Paul Zimmerman wrote: > On Mon, 20 Jan 2020 13:52:15 -0700 Paul Zimmerman <pauldzim@xxxxxxxxx> wrote: > > > On Mon, 20 Jan 2020 10:23:11 -0500 (EST) Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> wrote: > > > > > On Sun, 19 Jan 2020, Paul Zimmerman wrote: > > > > > > > I reported this regression last week (see > > > > https://lore.kernel.org/linux-usb/20200115153714.03d5b3aa@EliteBook/T/#u) > > > > but I got no response to my email. Today I have retested with > > > > 5.5-rc7 and verified that the problem still exists. So I am > > > > resending with a different subject line to see if anyone responds. > > > > > > > > The $subject patch causes a regression on my HP EliteBook laptop > > > > with a built-in USB bluetooth adapter. About 50% of the time, a > > > > suspend/resume cycle will cause the bluetooth adapter to stop > > > > working. > > > > > > > > The dmesg log below shows two suspend/resume cycles. At time > > > > 63.928 you can see the bluetooth adapter being successfully > > > > resumed, and at time 140.969 you can see it fail. After reverting > > > > the patch, the bluetooth adapter resumes 100% of the time. > > > > > > > > I also included below a lsusb -v of the bluetooth adapter. Is > > > > there any other debugging info you'd like me to send? > > > > > > It looks like your dmesg log was made without enabling debugging > > > messages in usbcore. Can you collect another log with debugging > > > messages turned on? > > > > > > echo 'module usbcore =p' > > > >/sys/kernel/debug/dynamic_debug/control > > > > > > Also, it might not hurt to collect and post a usbmon trace for a bad > > > suspend-resume cycle. > > > > Hi Alan, > > > > Thanks for responding. The new dmesg log and the usbmon trace are > > below. The dmesg shows a good suspend/resume followed by a bad one. > > The bluetooth device is usb 2-3.2 I believe. The usbmon trace is only > > for the failed suspend/resume case. It might be interesting to have a usbmon trace of a successful resume as well, for comparison. However I suspect it would just show that the new Get-Device-Descriptor request worked and everything else continued on normally. > I did some more debugging on this using ftrace, here is an annotated > log that shows what I think is happening on a failed resume. Note that > hub_port_connect_change() is the function that the patch modified to > call usb_get_device_descriptor() in some circumstances. > > This first call to hub_port_connect_change() is for a different device, > not the failing one. There are multiple other calls to that function in > the trace, but they are not for the device in question: > kworker/1:6-19987 [001] 7803.175058: funcgraph_entry: | hub_port_connect_change() { > kworker/1:6-19987 [001] 7803.175069: funcgraph_entry: ! 11911.151 us | usb_get_device_descriptor(); > kworker/2:5-20675 [002] 7803.179333: funcgraph_entry: | usb_probe_interface() { > > Starting here is a worker thread that is trying to setup the bluetooth > adapter after the resume: > kworker/u17:1-3175 [002] 7803.179457: funcgraph_entry: | hci_power_on() { > kworker/u17:1-3175 [002] 7803.179458: funcgraph_entry: | hci_dev_do_open() { > kworker/u17:1-3175 [002] 7803.179468: funcgraph_entry: | btusb_setup_intel() { > kworker/2:5-20675 [002] 7803.179480: funcgraph_exit: ! 147.596 us | } > > And here is a worker thread that is handling the connect change on the USB > port with the bluetooth device. This happens while the btusb_setup_intel() > function called by the other thread above is still running: > kworker/3:1-16790 [003] 7803.181323: funcgraph_entry: | hub_port_connect_change() { > kworker/3:1-16790 [003] 7803.181330: funcgraph_entry: | usb_get_device_descriptor() { > kworker/0:2-19962 [000] 7803.184885: funcgraph_entry: 6.016 us | hub_port_connect_change(); > kworker/0:2-19962 [000] 7803.187208: funcgraph_entry: 5.462 us | hub_port_connect_change(); > kworker/1:6-19987 [001] 7803.187835: funcgraph_exit: ! 12776.810 us | } > kworker/1:6-19987 [001] 7803.187846: funcgraph_entry: ! 767445.344 us | hub_port_connect_change(); > > By this point the failure has happened ("Bluetooth: hci0: Reading Intel > version information failed (-110)") , and it looks like somebody > queues another work to try setting up the bluetooth adapter again: > hciconfig-21074 [000] 7803.193549: funcgraph_entry: | hci_dev_open() { > kworker/1:6-19987 [001] 7803.955315: funcgraph_entry: ! 144039.307 us | hub_port_connect_change(); > kworker/u17:1-3175 [003] 7805.203325: funcgraph_exit: ! 2023855 us | } > kworker/u17:1-3175 [003] 7805.211728: funcgraph_exit: ! 2032269 us | } > kworker/u17:1-3175 [003] 7805.211731: funcgraph_exit: ! 2032273 us | } > hciconfig-21074 [000] 7805.211760: funcgraph_entry: | hci_dev_do_open() { > hciconfig-21074 [000] 7805.211777: funcgraph_entry: ! 3069605 us | btusb_setup_intel(); > > And here the usb_get_device_descriptor() call made by the USB worker thread > finally completes. It also fails ("kworker/3:1 timed out on ep0in len=0/18"): > kworker/3:1-16790 [003] 7808.277224: funcgraph_exit: ! 5095893 us | } > hciconfig-21074 [001] 7808.283313: funcgraph_exit: ! 3071554 us | } > hciconfig-21074 [001] 7808.283315: funcgraph_exit: ! 5089767 us | } > > So if I'm understanding this correctly, there are two threads that are > trying to access the USB bluetooth device at the same time. I have no > idea if that is how it's supposed to work. In fact it isn't, although in principle this shouldn't cause any trouble. It looks like your bluetooth device is deficient: It sometimes crashes if it receives a Get-Device-Descriptor request while it is busy with something else. Still, since there was no real connection change at the port, there's no reason to call hub_port_connect_change() here. Let's see if the patch below fixes your problem. Alan Stern Index: usb-devel/drivers/usb/core/hub.c =================================================================== --- usb-devel.orig/drivers/usb/core/hub.c +++ usb-devel/drivers/usb/core/hub.c @@ -1216,11 +1216,6 @@ static void hub_activate(struct usb_hub #ifdef CONFIG_PM udev->reset_resume = 1; #endif - /* Don't set the change_bits when the device - * was powered off. - */ - if (test_bit(port1, hub->power_bits)) - set_bit(port1, hub->change_bits); } else { /* The power session is gone; tell hub_wq */
