Hello,
On Friday 11 Nov 2016 00:27:52 Laurent Pinchart wrote:
> On Thursday 10 Nov 2016 13:42:34 Tony Lindgren wrote:
> > * Laurent Pinchart <[email protected]> [161110 13:29]:
> >> I had to disable CONFIG_USB_GADGET is compiling it as a module prevents
> >> selecting CONFIG_NOP_USB_XCEIV=y, which is a dependency for
> >> CONFIG_USB_EHCI_HCD_OMAP=m.
> >>
> >> The new configuration resulted in a few changes, among which the most
> >> notable is
> >>
> >> -# CONFIG_USB_MUSB_HOST is not set
> >> -# CONFIG_USB_MUSB_GADGET is not set
> >> -CONFIG_USB_MUSB_DUAL_ROLE=y
> >> +CONFIG_USB_MUSB_HOST=y
> >>
> >> I then get the same error as originally reported.
> >
> > Yeah OK, that's the problem.. We still have musb hardware
> > trying to do things on it's own and phy trying to detect
> > the state.
> >
> > Any ideas why we have a dependency like that in Kconfig?
>
> Well, with CONFIG_USB_GADGET disabled, I don't expect CONFIG_USB_MUSB_GADGET
> to be enabled. MUSB can only operate in host mode in that case, so musb->
> xceiv->otg->state = OTG_STATE_A_IDLE makes sense.
I've tried to investigate this but I'm not familiar enough with the MUSB
driver to reach any conclusion. Felipe, if you have time could you give me a
hand ?
To summarize the issue, on a pandaboard-es where the MUSB is wired to an OTG
connector with mode rightfully set to MUSB_PORT_MODE_DUAL_ROLE in DT, a kernel
configured with CONFIG_USB_MUSB_HOST=y (for instance because CONFIG_USB_GADGET
is disabled) will print an endless stream of the following meessage.
[ 2.766174] musb_bus_suspend 2586: trying to suspend as a_idle while active
musb_init_controller() performs the following actions
case MUSB_PORT_MODE_DUAL_ROLE:
status = musb_host_setup(musb, plat->power);
if (status < 0)
goto fail3;
status = musb_gadget_setup(musb);
if (status) {
musb_host_cleanup(musb);
goto fail3;
}
status = musb_platform_set_mode(musb, MUSB_OTG);
break;
and as gadget support is disabled musb_gadget_setup() compiles to a no-op
inline function. The system is thus configured in host mode by
musb_host_setup() with musb->xceiv->otg->state = OTG_STATE_A_IDLE. A later
call to musb_start() verifies the condition
if (musb->port_mode != MUSB_PORT_MODE_HOST &&
musb->xceiv->otg->state != OTG_STATE_A_WAIT_BCON &&
(devctl & MUSB_DEVCTL_VBUS) == MUSB_DEVCTL_VBUS) {
and sets musb->is_active to 1. Later, musb_bus_suspend() complains because
is_active is not 0.
What is wrong in that sequence ?
--
Regards,
Laurent Pinchart
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