XHCI DbC (debug port) problems
I'm assisting in debugging what appears to be a race condition in I2C code [0] on Intel ComputeStick STK1A32SC [1] devices. As part of that effort we were originally using an external USB<>RS232 adapter and "console=ttyUSB0,115200n8" but that can be extremely slow (connected to a real UART port) and the debug messages seem to prevent the issue occuring. We decided to switch to use the XHCI debug port and ordered a set of USB3 A<>A debug crossover cables [2]. We are following the kernel admin guide's USB3 debug port document [3] We've hit problems in getting the DbC port to work correctly and need some advice as to whether there is a kernel issue here? The target is using custom-built 4.20-rc4 kernels with all required modules built in. The original issue was first detected in Debian kernels v4.18.*, but didn't occur in v4.9. The ComputeStick devices have 2 USB ports, 1 is USB3, which the cable connects to. The host is using v4.18.18 (Fedora) and has usb_debug module loaded. Initially the host reported: usb 2-6: new SuperSpeed Gen 1 USB device number 9 using xhci_hcd usb 2-6: LPM exit latency is zeroed, disabling LPM. usb 2-6: language id specifier not provided by device, defaulting to English usb 2-6: New USB device found, idVendor=1d6b, idProduct=0011, bcdDevice= 0.10 usb 2-6: New USB device strings: Mfr=1, Product=2, SerialNumber=3 usb 2-6: rejected 1 configuration due to insufficient available bus power usb 2-6: no configuration chosen from 1 choice mtp-probe[32428]: checking bus 2, device 9: "/sys/devices/pci:00/:00:14.0/usb2/2-6" mtp-probe[32428]: bus: 2, device: 9 was not an MTP device fwupd[2590]: failed to add USB device 1d6b:0011: 1d6b:0011 is not supported: USB error on device 1d6b:0011 : Entity not found [-5] Due to "rejected 1 configuration due to insufficient available bus power" we then enabled the workaround: # echo 1 > /sys/bus/usb/devices/.../bConfigurationValue That got us further but then hits repeated -EPROTO errors: usb 2-6: no configuration chosen from 1 choice usb 2-6: new config #1 exceeds power limit by 660mA usb_debug 2-6:1.0: xhci_dbc converter detected usb 2-6: xhci_dbc converter now attached to ttyUSB0 xhci_dbc ttyUSB0: usb_serial_generic_write_bulk_callback - nonzero urb status: -71 The last line is repeated constantly several times each second. The first thing that has confused us is where is the host getting the "idProduct=0011" from? Looking at the xhci-dbgcap.h the only USB ID is #define DBC_PRODUCT_ID 0x0010 /* device 0010 */ and xhci-dbgcap.c seems to write it without change: dev_info = cpu_to_le32((DBC_DEVICE_REV << 16) | DBC_PRODUCT_ID); usb_serial does declare both 0x0010 and 0x0011 as aliases but that doesn't explain why the target is reported as 0x0011. We're wondering if the warning: "usb_serial_generic_write_bulk_callback - nonzero urb status: -71" is a regression or bug, rather than us missing something, since we've tried to do the same operation between two Fedora 4.18.18 PCs and got exactly the same results. Secondly, the "new config #1 exceeds power limit by 660mA" report, if we calculate correctly, suggests that bMaxPower being sent by the target is 900mA + 660mA = 1560mA, but cannot find in the code where bMaxPower is being set, if any. How is this set by the target? Any advice or experience as to what we might be missing? [0] https://bugs.freedesktop.org/show_bug.cgi?id=108714 [1] https://ark.intel.com/products/91064/Intel-Compute-Stick-STK1A32SC [2] https://www.datapro.net/products/usb-3-0-super-speed-a-a-debugging-cable.html [3] https://www.kernel.org/doc/html/v4.14/driver-api/usb/usb3-debug-port.html
Re: XHCI DbC (debug port) problems
On 11/12/2018 14:00, Mathias Nyman wrote: >> Any advice or experience as to what we might be missing? > > What does sudo lsusb -v on the host say about the target device? > What's the dbc status on the target? you did enable it right? > (on target, cat /sys/bus/pci/devices/:00:14.0/dbc) Is this documentation incomplete? https://www.kernel.org/doc/html/v4.14/driver-api/usb/usb3-debug-port.html There's no mention of needing to manipulate the 'dbc' node on either the host or the target. In fact, it wouldn't make sense to manipulate it on the target since we're trying to capture the kernel earlyprintk using "earlyprintk=xdbc" and the target doesn't necessarily reach userspace.
Re: XHCI DbC (debug port) problems
On 21/12/2018 16:37, Mathias Nyman wrote: > On 21.12.2018 17:53, Tj wrote: >> On 11/12/2018 14:00, Mathias Nyman wrote: >>>> Any advice or experience as to what we might be missing? >>> >>> What does sudo lsusb -v on the host say about the target device? >>> What's the dbc status on the target? you did enable it right? >>> (on target, cat /sys/bus/pci/devices/:00:14.0/dbc) >> >> Is this documentation incomplete? >> >> https://www.kernel.org/doc/html/v4.14/driver-api/usb/usb3-debug-port.html >> > > > That's the documentation for a old 4.14 kernel. > > see this instead: > https://www.kernel.org/doc/html/v4.19/driver-api/usb/usb3-debug-port.html > Thanks; hadn't realised we'd been looking at the older docs but it doesn't help. That specifically shows that writing to the 'dbc' node is a userspace procedure on the target - we're dealing with kernel earlyprintk. We have a custom kernel with all built-ins for testing with: $ egrep 'DBC|XHCI' .config CONFIG_USB_XHCI_HCD=y CONFIG_USB_XHCI_DBGCAP=y CONFIG_USB_XHCI_PCI=y CONFIG_EARLY_PRINTK_USB_XDBC=y and a command-line including "earlyprintk=xdbc" >From what you've said, and looking at our host dmesg reports, it looks like we're only getting confirmation that the host is detecting the debug cable and the target XHCI hardware *but not* the target OS's debug function (which might explain the unexpected idProduct) that should be enabled by CONFIG_EARLY_PRINTK_USB_XDBC. I've just reviewed the kernel config options and cannot see anything else that would appear to affect this. Thanks for helping out on this; we'd given up on making sense of it and not having a working example to compare against we're working blind.
Huawei Wireless data modem in Freescale i.MX6 Board
I'm trying to connect Huawei wireless data modem in Freescale i.MX6 Board. It's detected as a usb device and the result of lsusb is "Bus 002 Device 007: ID 12d1:140b Huawei Technologies Co., Ltd. EC1260 Wireless Data Modem HSD USB Card" But it's not mounted in /dev/disk/bu-id kindly help me to get it mounted and get the internet access in the Freescale i.MX6 Board through the USB Modem -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
Re: Huawei Wireless data modem in Freescale i.MX6 Board
Dear Dan Thanks for the reply. * PF the output(log.txt) of the below command. lsusb -v -d 12d1:140b * USB_Modeswitch operation also i've done. * Please let me know how to get the WWAN (I thing it's WLAN) connection manager in the ARM Board. (while connecting the USB broadband modem in x86, it's detecting as WLAN0 (in ifconfig) but the same is not shown in the ARM device for ifconfig Do we need to insmod any specific ko file for Wlan. please let me know. Thanks Regards, Thomas TJ. On Monday 30 September 2013 08:25 PM, Dan Williams wrote: On Mon, 2013-09-30 at 08:37 +, Thomas TJ wrote: I'm trying to connect Huawei wireless data modem in Freescale i.MX6 Board. It's detected as a usb device and the result of lsusb is "Bus 002 Device 007: ID 12d1:140b Huawei Technologies Co., Ltd. EC1260 Wireless Data Modem HSD USB Card" But it's not mounted in /dev/disk/bu-id kindly help me to get it mounted and get the internet access in the Freescale i.MX6 Board through the USB Modem What is the full lsusb output? Run "lsusb -v -d 12d1:140b". Many Huawei devices need to be "modeswitched" because by default their firmware presents itself not as a modem, but as a fake CD that contains the connection manager and driver. That is done by the usb_modeswitch program, and we need to first figure out whether that's necessary on your system and whether it's done. After that, you need a WWAN connection manager to make the actual data connection for your device. Dan -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
