On Fri, Nov 13, 2020 at 01:18:05PM +0000, John Boero wrote: > Thanks for the tips. > > I've spent some more time on this this morning. > It looks like it's not the dev after all. What isn't the dev? > Every interface in the dev is set NULL after init. I can't tell what this means. Please be more explicit. > Just like in the original Ubuntu bug 1827452 filed by someone else > the device seems to disconnect itself after uvcvideo initialization. > Then there is a 5 second pause before usb_ifnum_to_if tries > to iterate through its 8 interfaces - all of which are null. > It looks like uvc properly locks the dev, so maybe this could > be caused by any device being unplugged after init? More likely there is a bug in the uvcvideo driver. > The WARNING handle preserves USB function though, > and subsequent lsusb behaves fine: No, the WARN only writes a message to the system log. The "return" statement is what prevented the system from crashing. > $ lsusb | fold -w 80 > Bus 002 Device 002: ID 8087:8002 Intel Corp. 8 channel internal hub > Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 001 Device 002: ID 8087:800a Intel Corp. Hub > Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 004 Device 002: ID 0451:8140 Texas Instruments, Inc. TUSB8041 4-Port Hub > Bus 004 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub > Bus 003 Device 005: ID 1ea7:0064 SHARKOON Technologies GmbH 2.4GHz Wireless rech > argeable vertical mouse [More&Better] > Bus 003 Device 004: ID 145f:025c Trust Trust USB Microphone > Bus 003 Device 002: ID 1050:0407 Yubico.com Yubikey 4/5 OTP+U2F+CCID > Bus 003 Device 009: ID 0a5c:21e8 Broadcom Corp. BCM20702A0 Bluetooth 4.0 > Bus 003 Device 008: ID 0451:8142 Texas Instruments, Inc. TUSB8041 4-Port Hub > Bus 003 Device 006: ID 062a:4101 MosArt Semiconductor Corp. Wireless Keyboard/Mo > use > Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > Bus 006 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub > Bus 005 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > 8x (0-7) occurences of the following WARNING: > > [ 140.678756] usb 3-4: USB disconnect, device number 3 > [ 145.995855] ------------[ cut here ]------------ > [ 145.995863] dev interface is NULL in usb_ifnum_to_if > [ 145.995907] WARNING: CPU: 31 PID: 5617 at drivers/usb/core/usb.c:289 > usb_ifnum_to_if+0x58/0x80 You removed the most important part of the log message! What appears below this point? In fact, you should just post the entire log (or put it on a server somewhere and post a URL). Alan Stern
