Bdtyktl

i am running Debian 8 on iMx6 and everything works fine until i quickly turn the power off and on. (Quick Power Cycle) I am getting this on dmesg:

usb 1-1.6: device no response, device descriptor read/64, error -32

If i loggin with ssh, and do a restart command, i get the same error as the previous boot. But if i turn it off and wait at least 5 seconds, the USB starts with no problem.

Does someone knows what error -32 means?

Here the dmesg output:

root@vasoport:~# dmesg | grep usb

[    0.234446] usbcore: registered new interface driver usbfs

[    0.234522] usbcore: registered new interface driver hub

[    0.234614] usbcore: registered new device driver usb

[    0.234783] 2000000.aips-bus:usbphy_nop1 supply vcc not found, using dummy regulator

[    0.234907] 2000000.aips-bus:usbphy_nop2 supply vcc not found, using dummy regulator

[    1.319001] usbcore: registered new interface driver rtl8192cu

[    1.323787] usbcore: registered new interface driver cdc_ether

[    1.328389] usbcore: registered new interface driver MOSCHIP usb-ethernet driver

[    1.345027] usbcore: registered new interface driver cdc_acm

[    1.356196] usbcore: registered new interface driver usb-storage

[    1.361036] usbcore: registered new interface driver usbserial

[    1.365648] usbcore: registered new interface driver usbserial_generic

[    1.370922] usbserial: USB Serial support registered for generic

[    1.375698] usbcore: registered new interface driver cp210x

[    1.380013] usbserial: USB Serial support registered for cp210x

[    1.384702] usbcore: registered new interface driver ftdi_sio

[    1.389202] usbserial: USB Serial support registered for FTDI USB Serial Device

[    1.395287] usbcore: registered new interface driver option

[    1.399600] usbserial: USB Serial support registered for GSM modem (1-port)

[    1.406359] 2184800.usbmisc supply vbus-wakeup not found, using dummy regulator

[    1.460961] usb0: HOST MAC 42:3f:32:d8:7c:c0

[    1.464020] usb0: MAC ea:65:54:9f:3e:fe

[    1.592253] usbcore: registered new interface driver uvcvideo

[    1.621151] usbcore: registered new interface driver bcm203x

[    1.625616] usbcore: registered new interface driver btusb

[    1.629884] usbcore: registered new interface driver ath3k

[    1.773230] usb 1-1: new high-speed USB device number 2 using ci_hdrc

[    2.213248] usb 1-1.1: new low-speed USB device number 3 using ci_hdrc

[    2.313217] usb 1-1.1: device no response, device descriptor read/64, error -32

[    2.503239] usb 1-1.1: device no response, device descriptor read/64, error -32

[    2.703225] usb 1-1.1: new low-speed USB device number 4 using ci_hdrc

[    2.793222] usb 1-1.1: device no response, device descriptor read/64, error -32

[    2.993222] usb 1-1.1: device no response, device descriptor read/64, error -32

[    3.183224] usb 1-1.1: new low-speed USB device number 5 using ci_hdrc

[    3.190138] usbcore: registered new interface driver usbhid

[    3.194438] usbhid: USB HID core driver

[    3.197772] usbcore: registered new interface driver snd-usb-audio

[    3.371438] usb_otg_vbus: disabling

[    3.603314] usb 1-1.1: device not accepting address 5, error -32

[    3.703272] usb 1-1.1: new low-speed USB device number 6 using ci_hdrc

[    4.123304] usb 1-1.1: device not accepting address 6, error -32

[    4.136116] usb 1-1-port1: unable to enumerate USB device

[    4.373263] usb 1-1.6: new low-speed USB device number 7 using ci_hdrc

[    4.453252] usb 1-1.6: device no response, device descriptor read/64, error -32

[    4.643963] usb 1-1.6: device no response, device descriptor read/64, error -32

[    4.833317] usb 1-1.6: new low-speed USB device number 8 using ci_hdrc

[    4.943258] usb 1-1.6: device no response, device descriptor read/64, error -32

[    5.133246] usb 1-1.6: device no response, device descriptor read/64, error -32

[    5.323272] usb 1-1.6: new low-speed USB device number 9 using ci_hdrc

[    5.743293] usb 1-1.6: device not accepting address 9, error -32

[    5.843271] usb 1-1.6: new low-speed USB device number 10 using ci_hdrc

[    6.263291] usb 1-1.6: device not accepting address 10, error -32

It looks like something with the voltage i think, but is there a way to fix this on the software side?

Edit: Here are the Voltages 5V and 3V3 aswell as the iMx6 Reset Out pin which indicates, more and less, that the 3V3 voltage are ok.

Normal Start

Fast Start

You can find the error codes in errno.h, which includes errno-base.h. Returned error codes are negative by convention, so -32 is "broken pipe", which very likely is just a consequence of an USB read or write failure.

2184800.usbmisc supply vbus-wakeup not found, using dummy regulator

looks suspicious, especially if it doesn't appear when you wait before turning it on again.

First guess is that cycling the power too quickly doesn't fully discharge internal capacities in some USB-related chip, so if you turn it on again it's in a bad state, and the device initialization code either doesn't deal with that state, or can't deal with it because that state was never meant to happen.

It might be possible to fix it in software, by going over the datasheet with a fine toothed comb and paranoidly initializing everything to a proper state, with timeouts where necessary. But this will be no fun, take a long time, and you need the skills to write driver code. And then the bad state might be so crazy that this won't work.

So the simplest workaround is "don't power cycle too quickly".

So one solution would be an active capacitor discharge circuit using mosfets in 5V and 3V3 power supplies. Like this circuit: https://electronics.stackexchange.com/questions/201343/discharge-power-rail-with-mosfet

Mosfet circuit discharge capacitor: