On 08.04.2013 12:38, B, Ravi wrote: > Felipe > >> Hi, >> >> On Mon, Apr 08, 2013 at 12:25:38PM +0200, B, Ravi wrote: >>> Daniel >>> >>>> On 08.04.2013 09:57, B, Ravi wrote: >>>>>> Hi all, >>>>>> >>>>>> here are some patches to separate the HCD and gadget part >>>>>> of the >> musb >>>>>> driver so they can be deselected in Kconfig. They also make >>>>>> the >> driver >>>>>> keep track of the configured port mode that is set from DT, >>>>>> so the actual runtime configuration can be selected >>>>>> dynamically. >>>>>> >>>>>> One thing that is still broken is that once pm_suspend() >>>>>> was called >> on >>>>>> a musb device on a USB disconnect, the port won't wake up >>>>>> again >> when a >>>>>> device is plugged back in. >>>>> >>>>> This could be due to SESSION bit removal when root port is >> disconnected >>>> in otg_timer function. >>>> >>>> Not sure if we are thinking about the same details, but after >>>> debuging this a further, turns out that >>>> musb_platform_try_idle() eventually switches off the entire >>>> controller, which then leads to DRVBUS going >> low >>>> on the board. That, in turn, prevents the interrupt from being >> triggered >>>> on reconnect, because the host port is not powered anymore. >>>> >>>> I don't know yet how to cope with that, but for now, I simply >>>> disabled the call from musb_stage0_irq() to >>>> musb_platform_try_idle() locally. >>> >>> The otg_timer() gets invoked, which removes the session when no >>> device connected to root controller, this is required in otg or >>> dual role mode (Not for host-only mode). Because otg state is >>> un-defined till user's connected a-side of b-side of cable. >> >> Embedded hosts might also want this to save some power while no >> devices are connected. I guess most of those devices would rely on >> SRP or on a polling method to enable VBUS. > > Yes, in case of true otg, SRP wakesup the device to enable VBUS. > > By 'polling' I mean that e.g. every 2 >> seconds turn vbus on, if no device are enumerated in 200ms, then >> sleep for another 2 seconds. > > Yes, we had this workaround mechanism enabled on some earlier davinci > platform by setting the session periodically to check any device > connected for host or otg/dual-role controller to save VBUS power > when no device connected.
However, this workaround doesn't seem to work anymore. Anyway, I think we can address this issue separately from the patch set I submitted. Thanks, Daniel -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
