RE: [PATCH v4] usb: gadget: f_fs: add "no_disconnect" mode

From: Krzysztof Opasiak
Date: Thu Nov 13 2014 - 11:28:31 EST


Hello,

> -----Original Message-----
> From: Felipe Balbi [mailto:balbi@xxxxxx]
> Sent: Thursday, November 13, 2014 3:44 AM
> To: Felipe Balbi
> Cc: Robert Baldyga; David Cohen; gregkh@xxxxxxxxxxxxxxxxxxx; linux-
> usb@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx;
> mina86@xxxxxxxxxx; andrzej.p@xxxxxxxxxxx; m.szyprowski@xxxxxxxxxxx;
> k.opasiak@xxxxxxxxxxx
> Subject: Re: [PATCH v4] usb: gadget: f_fs: add "no_disconnect" mode

(...)

> > > David, you have been messing with ffs lately, can I get a
> Tested-by
> > > from you on this patch ?
> >
> > ping. David ? Any chance you can test this one out ?
>
> a reminder on this request, it's getting close to tree lockdown
> (probably another 2 to 3 weeks).

I have tested this patch today but I'm afraid that I can't give
tested-by tag:

When I kill the daemon and then reconnect my device I get on my host:

[776092.877175] usb 1-1.1: can't set config #1, error -32

While on device there is only:

[ 2147.035340] configfs-gadget gadget: high-speed config #1: The only
one

Moreover, I'm not very enthusiastic about the convention in which we
allow
to reconnect the device without any changes.

In my opinion when daemon has been killed we should allow user to finish
communication with other functions and then simply unbind our gadget.
This should happen not only on reconnection but also when host is trying
to enable configuration which contains this function "zombie".
This function is not fully operational so it is very good idea to
allow user to finish his job with other functions but when he reconnects
the
device we should unbind gadget to notify userspace that something is
wrong.
The same when we switch configuration.

What do you think about this Michal and Felipe?

--
Krzysiek

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