On 14/05/2015 at 16:16:12 -0500, Bin Liu wrote : > I think I found the root cause of the problem: board design issue - I > bet the custom board has too much cap on VBUS line. It should be < > 10uF. > We have a custom board that exhibits the issue but it only has a 100nF cap on VBUS. > I just noticed I have the Jumper 36 on on my EVM, which adds 154.7uF > cap on VBUS causing discharge takes ~20sec. After removed the jumper, > which leaves only 4.7uF cap on VBUS, now it only takes ~0.4sec to > generate Disconnect IRQ. Here is the log. > > root@:~# [ 2504.893123] musb-hdrc musb-hdrc.0.auto: usbintr (1) epintr(0) > [ 2504.899198] musb-hdrc musb-hdrc.0.auto: <== DevCtl=99, int_usb=0x1 > [ 2504.912751] zero gadget: suspend > [ 2504.916145] zero gadget: zero_suspend > [ 2505.303937] musb-hdrc musb-hdrc.0.auto: usbintr (20) epintr(0) > [ 2505.310072] musb-hdrc musb-hdrc.0.auto: <== DevCtl=88, int_usb=0x20 > [ 2505.325355] zero gadget: reset config > [ 2507.303288] musb-hdrc musb-hdrc.0.auto: Poll devctl 80 (b_idle) > -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- 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
