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    SubjectRE: [RFC][PATCH 0/2] Avoiding DWC3 transfer stalls/hangs when using adb over f_fs
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    >>>> Hey all,
    >>>> I wanted to send these out for comment and thoughts.
    >>>>
    >>>> Since ~4.20, when the functionfs gadget enabled scatter-gather
    >>>> support, we have seen problems with adb connections stalling and
    >>>> stopping to function on hardware with dwc3 usb controllers.
    >>>> Specifically, HiKey960, Dragonboard 845c, and Pixel3 devices.
    >>>
    >>> Any chance this:
    >>>
    >>> https://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git/commit/
    >>> ?h=testing/next&id=f63333e8e4fd63d8d8ae83b89d2c38cf21d64801
    >> This is a different issue. I have tried initializing num_sgs when debugging this adb stall problem, but it didn't help.
    >
    > So multiple folks have run through this problem, but not *one* has tracepoints collected from the issue? C'mon guys. Can someone, please, collect tracepoints so we can figure out what's actually going on?
    >
    > I'm pretty sure this should be solved at the DMA API level, just want to confirm.
    I have sent you the tracepoints long time ago. Also my analysis of the problem (BTW, I don't think the tracepoints helped much). It's basically a logic problem in function dwc3_gadget_ep_reclaim_trb_sg().
    I can try dig into my old emails and resend, but that is a bit hard to find.

    -Fei

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