Alexandre, On Thu, May 14, 2015 at 4:26 PM, Alexandre Belloni <alexandre.belloni@xxxxxxxxxxxxxxxxxx> wrote: > 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. Have you measured the VBUS discharging? Is there any way to share your schematics? Regards, -Bin. > >> 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
