On Tue, 20 Jun 2017, Gil Weber wrote: > Hello, > I have a device running on Atmel AT91 SAM9X5 processor with an USB modem > (Sagemcom Hilo 3G). Until now, it worked fine... Our firmware was based on > Kernel 3.12. USB Host driver is ehci-atmel. > > We recently upgrade to a Kernel 4.9. > Now one of our customer is having issues with a couple of devices. > It seems that the modem is disconnected from USB... with the error > "usb usb1-port2: disabled by hub (EMI?), re-enabling...". > > After some search, I have seen that this could be caused by a bad cable... > But the modem is integrated on the PCB, so, except if we have an hardware issue > it is not the cause. Also, the same device works perfect with 3.12 kernel. > No disconnection, no EMI message in trace log, ... > > > So my question is, from your experience, what could be the cause of this > disconnection? Is this necessarly an EMI? Such disconnections are carried out automatically by the hardware. The cause does not have to be EMI, but finding the cause is usually extremely difficult. It might even be that a change in the software causes the hardware to behave differently. > If yes, could it worked "by luck" in 3.12? From what I see, the code around > this EMI detection is pretty similar between 3.12 and 4.9... but maybe the > timing can have impact on it? Maybe. It's impossible to say. If you have enough time and energy, you could try running some of the kernels between 3.12 and 4.9 to see at which version these disconnections start to happen. Alan Stern > Here is a trace log: > > [47501.022000] usb usb1-port2: disabled by hub (EMI?), re-enabling... > [47501.022000] usb 1-2: USB disconnect, device number 81 > [47501.074000] qcserial ttyUSB0: Qualcomm USB modem converter now disconnected > from ttyUSB0 > [47501.089000] qcserial 1-2:1.2: device disconnected > [47505.864000] usb 1-2: new high-speed USB device number 82 using atmel-ehci > [47506.005000] usb 1-2: New USB device found, idVendor=05c6, idProduct=9009 > [47506.007000] usb 1-2: New USB device strings: Mfr=3, Product=2, > SerialNumber=0 > [47506.010000] usb 1-2: Product: Qualcomm CDMA Technologies MSM > [47506.014000] usb 1-2: Manufacturer: Qualcomm, Incorporated > [47506.064000] usb 1-2: selecting invalid altsetting 1 > [47506.064000] usb 1-2: Could not set interface, error -22 > [47506.194000] qcserial 1-2:1.2: Qualcomm USB modem converter detected > [47506.231000] usb 1-2: Qualcomm USB modem converter now attached to ttyUSB0 > > > I have this log over and over... once disconnected from USB, my application > do a reset of the modem which is then re-detected, then it work for a > few minutes. > > > > Thanks in advance for helping me with this issue :-) > Gil -- 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
