On Tue, May 10, 2016 at 9:17 AM, Craig McQueen <craig.mcqueen@xxxxxxxxxxxxxx> wrote: > Yegor Yefremov wrote: >> Hi Craig, >> >> On Tue, May 10, 2016 at 8:08 AM, Craig McQueen >> <craig.mcqueen@xxxxxxxxxxxxxx> wrote: >> > I previously wrote: >> >> I previously wrote: >> >> > I previously wrote: >> >> > > >> >> > > I have a D-Link DWA-140 USB Wi-Fi device which is rt2800 based >> >> > > (5392 chipset). I've been testing it on a BeagleBone Black >> >> > > running an Ubuntu >> >> > > 16.04 image (4.4.6 kernel), with a USB hub. >> >> > > >> >> > > When I unplug the Wi-Fi device from the USB hub, and it's >> >> > > connected to an access point, and then I unplug it, the OS appears to >> lock up. >> >> > > I get messages about a soft lockup on the serial console: >> >> > > >> >> > > [ 9736.136702] NMI watchdog: BUG: soft lockup - CPU#0 stuck for 22s! >> >> > > [kworker/u2:0:1129] [ 9764.136701] NMI watchdog: BUG: soft lockup >> >> > > - >> >> > > CPU#0 stuck for 22s! [kworker/u2:0:1129] [ 9792.136701] NMI >> watchdog: >> >> > > BUG: soft lockup - CPU#0 stuck for 22s! [kworker/u2:0:1129] [ >> >> > > 9820.136699] NMI >> >> > > watchdog: BUG: soft lockup - CPU#0 stuck for 22s! >> >> > > [kworker/u2:0:1129] [ 9848.136696] NMI watchdog: BUG: soft lockup >> >> > > - >> >> CPU#0 stuck for 22s! >> >> > > [kworker/u2:0:1129] >> >> > > >> >> > > This will repeat indefinitely, until I unplug the hub, which >> >> > > resolves the soft lockup and then the system seems to function >> normally. >> >> > > >> >> > > I've attached a dmesg log of the soft lockup stack traces. They >> >> > > seem to indicate a lockup in workqueue rt2x00usb_work_rxdone() >> >> > > (specifically in >> >> > > usb_hcd_submit_urb() called from rt2x00usb_kick_rx_entry() called >> >> > > from rt2x00usb_clear_entry()). >> >> > > >> >> > > I originally found this bug on a 3.14.x kernel built with Yocto >> >> > > for a BeagleBone Black-based product. So it seems this is a bug >> >> > > that has been around for some time. >> >> > >> >> > I should also note that on the 3.14.x Yocto-built kernel on >> >> > BeagleBone Black, this bug does not occur if the rt2800 device is >> >> > unplugged directly from the BBB's USB port. It only occurs if unplugged >> from a hub. >> >> > >> >> > I have tested this on an i586 based eBox-3310A mini-PC running >> >> > Debian 8.4, which has a 3.16.0 kernel, with the same hub and same >> >> > rt2800 device. But I was not able to reproduce this issue. >> >> >> >> There is a patch for the AM335x musb driver that seems to fix this: >> >> >> >> http://marc.info/?l=linux-usb&m=146173995117456&w=2 >> >> >> >> So it seems that this issue's root cause is in the AM335x USB >> >> interrupt handling, and not the Wi-Fi rt2800 driver. >> > >> > Having applied two AM335x USB patches in the 3.14.49 kernel, that does >> seem to resolve the soft lock-up on the RX side. The two patches are: >> > >> > http://marc.info/?l=linux-usb&m=146173995117456&w=2 >> > http://marc.info/?l=linux-usb&m=146222355213935&w=2 >> > >> > But I am finding there is still a lock-up issue when unplugging from a hub, >> this time on the TX side. It is more likely if there is Wi-Fi traffic in progress >> when the unplug occurs. I'm attaching a log. Essentially there are a heap of >> lines (100 or so per second): >> > >> > [ 1866.693511] ieee80211 phy7: rt2800usb_tx_sta_fifo_read_completed: >> > Warning - TX status read failed -71 >> > >> > Which finally stop shortly after USB disconnect is detected: >> > >> > [ 1866.985854] usb 1-1.3: USB disconnect, device number 10 >> > >> > However that disconnect message is typically 30-90 seconds after the >> unplug happened. It seems that the USB disconnect detection is delayed due >> to the CPU load of the TX. >> > >> > I also sometimes see a kernel panic. That can occur whether connected to a >> USB hub or directly to the on-board USB port. See the attached log. >> > >> > I'm not so familiar with either the Wi-Fi or USB stacks in the Linux >> > kernel, so I would appreciate any advice with debugging and fixing >> > this. (My previous investigations indicate these issues are present in >> > both 3.14.x kernel and 4.4.6 kernel. I'm more familiar with working >> > with the 3.14.x kernel under Yocto, but I could try moving to 4.4.6 >> > kernel for Ubuntu. I'm open to advice on which to investigate on.) >> >> Take a look at this patch: http://marc.info/?l=linux- >> usb&m=146222355213935&w=2 >> >> If it fixes your issue please provide your "tested-by" tag here. > > Hi Yegor, > > I am using that patch, and I referred to it in my last message. But it doesn't fix this issue. Have missed that. I've made following test with am335x based device and a Ralink Technology, Corp. RT5370 Wireless Adapter attached vie USB hub: root@baltos:~# lsusb -t /: Bus 02.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M /: Bus 01.Port 1: Dev 1, Class=root_hub, Driver=musb-hdrc/1p, 480M |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/4p, 480M |__ Port 1: Dev 4, If 0, Class=Vendor Specific Class, Driver=rt2800usb, 480M during nuttcp test session I unplug WLAN dongle and get following kernel messages (kernel 3.18.32 with [1]) ieee80211 phy2: rt2800usb_tx_sta_fifo_read_completed: Warning - TX status read failed -71 hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) ieee80211 phy2: rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x1700 with error -110 hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) hub 1-1:1.0: hub_port_status failed (err = -110) ieee80211 phy2: rt2x00usb_vendor_request: Error - Vendor Request 0x07 failed for offset 0x0438 with error -110 hub 1-1:1.0: hub_port_status failed (err = -110) [1] http://marc.info/?l=linux-usb&m=146222355213935&w=2 Yegor -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
