[Bug 220491] usb_storage connected SD card disconnects/reconnects on resume from suspend

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https://bugzilla.kernel.org/show_bug.cgi?id=220491

--- Comment #56 from Paul Ausbeck (paula@alumni.cse.ucsc.edu) ---
Created attachment 308729
  --> https://bugzilla.kernel.org/attachment.cgi?id=308729&action=edit
usbcore log of disconnect following reset

Mathias: I apologize for not immediately getting back. I am still working on
this problem, albeit slowly, mostly due to my getting older. Unfortunately
neither of your patches fixed my particular ativ0 SD card disconnect issue,
though the last did help to jump-start investigation.

I am slowly instrumenting the ativ9 kernel to help me to understand the code
path to disconnect. In addition adding/changing logging information, I've made
a few changes to the code to get past some bailout points. I now have a trace
where the reset code detects that the device, not hub port, is not responding
properly and initiates a disconnect.

I have attached a log of the entire sequence with everything else stripped out.
I've stripped other things as the log is long enough as it is.

I've thought from the outset that it may be necessary to disconnect and
reconnect the device in order to successfully patch around this problem. I've
gotten to the point where I can begin to see how to start coding on a patch to
accomplish that and I will continue on that path unless I get a better
suggestion.

One thing I haven't looked at yet is the warm reset concept. As far as I can
tell, the current code is performing a "hot" reset. I think maybe I should look
at trying a "warm" reset instead. If this seems important to anyone, please
weigh in.

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