On Tue, Aug 04, 2015 at 04:23:02PM +0200, Gregory CLEMENT wrote: > Hi again, > On 04/08/2015 15:08, Gregory CLEMENT wrote: > > Hi Bin, > > > > On 02/07/2015 19:05, Bin Liu wrote: > >> Hi, > >> > >> On Thu, Jul 2, 2015 at 2:16 AM, Gregory CLEMENT > >> <gregory.clement@xxxxxxxxxxxxxxxxxx> wrote: > >>> Hi Felipe, > >>> > >>> On 27/05/2015 11:42, Alexandre Belloni wrote: > >>>> Hi, > >>>> > >>>> On 26/05/2015 at 09:51:18 -0500, Felipe Balbi wrote : > >>>>> On Thu, May 14, 2015 at 04:36:33PM -0500, Bin Liu wrote: > >>>>>> 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? > >>>>> > >>>>> Alexandre, any further comments ? > >>>>> > >>>> > >>>> Yeah, I have just got more info. > >>>> > >>>> This is the relevant part of the schematic: > >>>> http://free-electrons.com/~alexandre/usb.png > >>>> > >>>> The total VBUS capacitance is 200nF and the USB0 pins are connected > >>>> directly to the AM3358 pins. U1 is actually not fitted. > >>>> > >>>> We didn't measure VBUS discharging but we observe the OTG pin sensing > >>>> stops when plugging an OTG cable without any device. > >>> > >>> Do you have any news about this topic? > >>> > >>> > >>> Is there something else that we can do to help solving this issue? > >> > >> In the case of CONFIG_USB_MUSB_DUAL_ROLE=y and dr_mode=otg, how is the > >> gadget driver configured? It has to be a module not built-in. > > > > Indeed when I configured CONFIG_USB_MUSB_HDRC=m and CONFIG_USB_MUSB_DSPS=m > > it worked seamless. > > > > Actually it didn't worked. And now sometimes I even received continuously > the following message: > > musb_bus_suspend 2484: trying to suspend as a_wait_vfall while active this is likely because your VBUS hasn't dropped below 0.8V fast enough. I could only trigger this message in that situation. Use a scope to poke at VBUS and see how long is takes to reach 0.8V, this could all be cause by too much capacitance on VBUS line. cheers -- balbi
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