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    SubjectRe: [PATCH] usb-musb: keep VBUS on when device is disconnected
    On Mon, Mar 27, 2017 at 09:59:47AM -0700, Tony Lindgren wrote:
    > * Moreno Bartalucci <moreno.bartalucci@tecnorama.it> [170327 09:23]:
    > > If I understood your patch, however, if the device (anyone, not just my one) takes longer to switch, VBUS is deasserted anyway.
    >
    > Yeah some of them can take at least 10 seconds even to enumerate.
    > So probably we need to have to have some longer timeout set for
    > OTG_STATE_A_WAIT_BCON, like 20 or 30 seconds.
    >
    > > Although this patch is working for me, personally I would prefer a solution which would not deassert VBUS. At least on a host only port. Honestly I don’t know how a dual role port should work.
    >
    > It's been really long time since I read the OTG spec. There
    > may be some diagram showing the required timeouts in the spec
    > if there is one for VBUS.
    >
    > Maybe we need some property to specify vbus-always-on-in-host-mode?

    The MUSB otg state machine has been changed in many place since the last
    time I looked at it, and I am not sure how exactly it works now.

    If the $subject patch can correctly keep the VBUS on for host-only mode,
    we can somehow use dr_modei value to distinguish the mode. We don't have
    to create a new vbus-always-on-in-host-mode flag. VBUS has to be always
    on in host-only mode anyway, until some error condition happens.

    Regards,
    -Bin.

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