On 12/16/2014 02:15 PM, Peter Chen wrote: > On Tue, Dec 16, 2014 at 10:50:59AM +0530, Sanchayan Maity wrote: >> On 12/16/2014 06:16 AM, Peter Chen wrote: >>> On Mon, Dec 15, 2014 at 02:59:31PM +0530, Sanchayan Maity wrote: >>>> Hello, >>>> >>>> On 12/15/2014 07:42 AM, Peter Chen wrote: >>>>> On Fri, Dec 12, 2014 at 06:55:36PM +0530, Sanchayan Maity wrote: >>>>>> Hello, >>>>>> >>>>>> On 12/12/2014 07:21 AM, Peter Chen wrote: >>>>>>> On Thu, Dec 11, 2014 at 08:34:45AM -0600, Felipe Balbi wrote: >>>>>>>> Hi, >>>>>>>> >>>>>>>> On Thu, Dec 11, 2014 at 04:08:43PM +0530, Sanchayan Maity wrote: >>>>>>>>> Hello, >>>>>>>>> >>>>>>>>> I am working on a Freescale Cortex-A5 Vybrid Processor. The chip core >>>>>>>>> is clocked at 500MHz and the USB IP core for this is by Chip-idea. I >>>>>>>>> am running a 3.18-rc5 kernel on it and trying to use the USB gadget >>>>>>>>> functionality. To be more specific the CDC ECM class. Currently, I >>>>>>>>> cannot use this properly. If I use just "ping" to check, it works >>>>>>>>> fine, but, after running iperf, even one transaction doesn't complete >>>>>>>>> or completes rarely. Checking the CDC Ether interface with Wireshark >>>>>>>>> shows, TCP Dup Ack messages and checking the USB bus with Wireshark, >>>>>>>>> shows packets with USB Protocol Error -71 at one point and after that >>>>>>>>> packets with USB connection Reset -104 error. If it's of any >>>>>>>>> significance, I have Arch Linux with the 3.18 kernel running on my >>>>>>>>> laptop with which the Vybrid connects. On the host side, the only >>>>>>>>> error dmesg shows is "kevent 12 may have been dropped". I guess this >>>>>>>>> is connected to the "TCP Previous Segment not captured" and "TCP Dup >>>>>>>>> ACK" messages. >>>>>>>>> >>>>>>>>> My script for the gadget configuration is as below: >>>>>>>>> >>>>>>>>> /bin/mount none /mnt -t configfs >>>>>>>>> /bin/mkdir /mnt/usb_gadget/g1 >>>>>>>>> cd /mnt/usb_gadget/g1 >>>>>>>>> /bin/mkdir configs/c.1 >>>>>>>>> /bin/mkdir functions/ecm.0 >>>>>>>>> /bin/mkdir strings/0x409 >>>>>>>>> /bin/mkdir configs/c.1/strings/0x409 >>>>>>>>> echo 0xa4a2 > idProduct >>>>>>>>> echo 0x0525 > idVendor >>>>>>>>> echo Freescale123 > strings/0x409/serialnumber >>>>>>>>> echo Freescale > strings/0x409/manufacturer >>>>>>>>> echo "USB Serial Gadget" > strings/0x409/product >>>>>>>>> echo "Conf 1" > configs/c.1/strings/0x409/configuration >>>>>>>>> echo 200 > configs/c.1/MaxPower >>>>>>>>> ln -s functions/ecm.0 configs/c.1 >>>>>>>>> echo ci_hdrc.0 > UDC >>>>>>>>> /sbin/ifconfig usb0 up >>>>>>>>> /sbin/ifconfig usb0 192.168.1.10 >>>>>>>>> >>>>>>>>> I have debug prints in the udc.c and u_ether.c using pr_debug and >>>>>>>> >>>>>>>> just a little hint, use any of the dev_*() macros next time, they'll >>>>>>>> print the device name which helps figuring out which UDC you're using. >>>>>>>> >>>>>>>> Based on ci_hdrc.0 above, I suppose it's chipidea and Peter Chen >>>>>>>> maintains that one, it really helps adding maintainers to Cc list. >>>>>>>> >>>>>>>>> enable them when required using dynamic debug. Without running iperf, >>>>>>>>> using ping gives me a sequence of prints as below: >>>>>>>>> >>>>>>>>> [ 277.434409] In eth_start_xmit >>>>>>>>> [ 277.434517] In UDC irq >>>>>>>>> [ 277.434553] In usb_gadget_giveback_request >>>>>>>>> [ 277.434567] In tx_complete >>>>>>>>> [ 277.435443] In UDC irq >>>>>>>>> [ 277.435477] In usb_gadget_giveback_request >>>>>>>>> [ 277.435491] In rx_complete >>>>>>>>> [ 277.435517] In rx_submit >>>>>>>>> [ 277.435601] In eth_start_xmit >>>>>>>>> [ 277.436441] In UDC irq >>>>>>>>> [ 277.436465] In usb_gadget_giveback_request >>>>>>>>> [ 277.436478] In rx_complete >>>>>>>>> [ 277.436493] In rx_submit >>>>>>>>> [ 277.436520] In usb_gadget_giveback_request >>>>>>>>> [ 277.436533] In tx_complete >>>>>>>>> [ 278.434865] In eth_start_xmit >>>>>>>>> [ 278.434959] In UDC irq >>>>>>>>> [ 278.434993] In usb_gadget_giveback_request >>>>>>>>> [ 278.435006] In tx_complete >>>>>>>>> [ 278.435881] In UDC irq >>>>>>>>> [ 278.435910] In usb_gadget_giveback_request >>>>>>>>> [ 278.435923] In rx_complete >>>>>>>>> [ 278.435946] In rx_submit >>>>>>>>> >>>>>>>>> After running iperf without debug prints and then enabling before >>>>>>>>> using ping gives me a sequence of prints as below >>>>>>>>> [ 81.989827] In UDC irq >>>>>>>>> [ 81.989871] In usb_gadget_giveback_request >>>>>>>>> [ 81.989886] In rx_complete >>>>>>>>> [ 81.989905] In rx_submit >>>>>>>>> [ 82.989892] In UDC irq >>>>>>>>> [ 82.989951] In usb_gadget_giveback_request >>>>>>>>> [ 82.989967] In rx_complete >>>>>>>>> [ 82.989992] In rx_submit >>>>>>>>> [ 83.990064] In UDC irq >>>>>>>>> [ 83.990126] In usb_gadget_giveback_request >>>>>>>>> [ 83.990142] In rx_complete >>>>>>>>> [ 83.990167] In rx_submit >>>>>>>>> [ 84.990007] In UDC irq >>>>>>>>> [ 84.990049] In usb_gadget_giveback_request >>>>>>>>> [ 84.990064] In rx_complete >>>>>>>>> [ 84.990083] In rx_submit >>>>>>>>> [ 85.990085] In UDC irq >>>>>>>>> [ 85.990147] In usb_gadget_giveback_request >>>>>>>>> [ 85.990163] In rx_complete >>>>>>>>> [ 85.990188] In rx_submit >>>>>>>>> >>>>>>>>> If I force a full speed configuration for this USB client port, I get >>>>>>>>> a slightly more reliable operation where iperf can run for may be half >>>>>>>>> an hour or so or almost an hour before it falls through. Putting in a >>>>>>>>> delay of 100-150 microseconds in eth_start_xmit also improves it like >>>>>>>>> full speed, but, still not reliable. If I run iperf with debug prints >>>>>>>>> enable, this gives similar results to full speed config. After the >>>>>>>>> failure of iperf test, even ping doesn't work. Bringing down this usb0 >>>>>>>>> interface and then up again makes ping work again. I do realize that >>>>>>>>> putting debug prints or delays like this is not the right thing to do, >>>>>>>>> especially in ISR, but, just trying to debug. This is my first time >>>>>>>>> digging in the USB stack. >>>>>>>>> >>>>>>>>> Based on the above, it seems there might a subtle bug or race >>>>>>>>> condition somewhere in the execution call chain which I have not been >>>>>>>>> able to trace yet. Can someone give me some pointers on how I can dig >>>>>>>>> and debug further?. >>>>>>>> >>>>>>> >>>>>>> I just tried latest usb-next with i.mx6 platform, it works ok with >>>>>>> 10 mins iperf bi-direction test. >>>>>> >>>>>> We did think that it is probably an issue seen with Vybrids only. >>>>>> >>>>> >>>>> - Check Vybrid errata to see if any missing in code >>>> >>>> I had not checked the Vybrid errata. There are two erratas and I think one >>>> of them might be relevant to the issue. >>>> >>>> e6857: Adding dTD to Primed Endpoint may not be recognized >>>> >>> > > Sorry, I made a mistake, it is a new errata, and does not be included in > the code. All imx project uses 2.0a or 2.50a which does not need this > errata, and Vybrid uses 2.40a core which needs this errata, I will do a > patch for this soon, but before that, would you read your ID register > ($BASE + 0x0) for me? I would like to confirm if your REVISION value > is 0100b. > As per the reference manual and also the devmem2 readout of the USB ID register the value is 0xE481FA05. This gives a Revision number 0x81 for the controller core and 0x05 for the ID viz. configuration number. -Regards, Sanchayan. -- 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
