On Tue, Aug 25, 2020, at 12:27 AM, Felipe Balbi wrote: > "Sid Spry" <sid@xxxxxxx> writes: > > > On Mon, Aug 24, 2020, at 1:16 AM, Felipe Balbi wrote: > >> > >> Hi, > >> > >> "Sid Spry" <sid@xxxxxxx> writes: > >> > See title. I'm getting this even when using shell commands, so I don't > >> > think it is my program. Creating anything else, like ncm.usb0, will > >> > work. > >> > >> which kernel version? which usb controller? which platform? > >> > > > > Kernel 5.4.45 compiled for a Raspberry Pi 4, the UDC is a DWC2. > > great. Latest v5.4 stable is v5.4.60. There have been a few fixes in > dwc2 and gadget drivers between .45 and .60. Just to rule out a problem > that was already fixed, could you merge v5.4.60 to your kernel and try > again? > > > On another device (Allwinner based) I could add one serial gadget > > but not two, and I though this may have been endpoint exhaustion. Now > > I am not so sure. > > It could exhaustion of Interrupt-capable endpoints. It depends on how > the gadget and the UDC were configured. > Should have been obvious, but yes, this fixes it. Thanks. In meantime have been finding a bunch of other behavior I can *explain* but definitely feel is weird, so will try talking about that on list.