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    SubjectRe: [PATCH 2/3] usb: gadget: composite: Split composite reset and disconnect
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    Jack Pham wrote:
    > Hi Thinh,
    >
    > On Fri, Jan 08, 2021 at 02:19:30AM +0000, Thinh Nguyen wrote:
    >> Hi Wesley,
    >>
    >> Felipe Balbi wrote:
    >>> Hi,
    >>>
    >>> Wesley Cheng <wcheng@codeaurora.org> writes:
    >>>> +void composite_reset(struct usb_gadget *gadget)
    >>>> +{
    >>>> + /*
    >>>> + * Section 1.4.13 Standard Downstream Port of the USB battery charging
    >>>> + * specification v1.2 states that a device connected on a SDP shall only
    >>>> + * draw at max 100mA while in a connected, but unconfigured state.
    >>> The requirements are different, though. I think OTG spec has some extra
    >>> requirements where only 8mA can be drawn max. You need to check for the
    >>> otg flag. Moreover, USB3+ spec has units of 150mA meaning the device
    >>> can't draw 100mA (IIRC).
    >>>
    >> We see issue with this patch series. For our device running at SSP, the
    >> device couldn't recover from a port reset and remained in eSS.Inactive
    >> state.
    >>
    >> This patch series is already in Greg's usb-testing. Please review and
    >> help fix it.
    >>
    >> We can see the failure once the patch "usb: gadget: configfs: Add a
    >> specific configFS reset callback" is introduced.
    > Hmm. Does your device use a legacy USB2 PHY (not generic PHY) driver,
    > and does it implement the usb_phy_set_power() callback? Because
    > otherwise this new configfs_composite_reset() callback would not have
    > changed from the original behavior since the newly introduced (in patch
    > 1/3) dwc3_gadget_vbus_draw() callback would simply be a no-op if
    > dwc->usb2_phy is not present.
    >
    > If it does turn out to be something with your PHY driver's set_power(),
    > it's still puzzling since it's directed to only the usb2_phy, so I'm
    > curious how telling it to draw 100mA could affect SSP operation at all.
    >
    > Thanks,
    > Jack

    So, I ran some more tests. It seems like this new change affects some
    timing in my setup that triggers this failure. I tried to add some
    printouts to look into it further, but somehow that reduces the failure
    rate significantly. This doesn't seem related to power drawing as it
    doesn't update usb2_phy for SSP as you said.

    After switching my HW setup, the problem seems to go away. I guess we
    can ignore this since the code path looks to be the same as previous.

    BR,
    Thinh
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