From: Felipe Balbi <felipe.balbi@linux.intel.com>
To: Alan Stern <stern@rowland.harvard.edu>,
Andrey Konovalov <andreyknvl@google.com>
Cc: USB list <linux-usb@vger.kernel.org>,
Alexander Potapenko <glider@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: Re: Pass transfer_buffer to gadget drivers
Date: Wed, 19 Jun 2019 09:36:47 +0300 [thread overview]
Message-ID: <874l4mf5ds.fsf@linux.intel.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1906180948100.1659-100000@iolanthe.rowland.org>
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Hi,
Alan Stern <stern@rowland.harvard.edu> writes:
>> Also, does the gadget subsystem guarantee, that we get the complete()
>> callback for the DATA stage of the OUT control request before we get a
>> setup() callback for the next control request if there's any?
>
> As I recall, this isn't mentioned in the documentation. But the UDC
> drivers I know of do behave that way, and it's reasonable to assume
> they all do.
>
> After all, a data-stage transfer can't complete _after_ the next Setup
> packet arrives. Reception of a new Setup packet invalidates all
> ongoing control transfers.
Considering that the gadget API handles one stage at a time, it would be
impossible for this to not be the case :-)
UDCs start a trasnfer only for the setup phase, then process the
control request to decide what to do next.
--
balbi
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next prev parent reply other threads:[~2019-06-19 6:36 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-07 11:44 Pass transfer_buffer to gadget drivers Andrey Konovalov
2019-06-07 12:02 ` Felipe Balbi
2019-06-07 12:14 ` Andrey Konovalov
2019-06-07 12:25 ` Felipe Balbi
2019-06-07 12:32 ` Andrey Konovalov
2019-06-07 12:43 ` Felipe Balbi
2019-06-07 12:45 ` Andrey Konovalov
2019-06-07 14:04 ` Alan Stern
2019-06-07 14:38 ` Andrey Konovalov
2019-06-07 15:02 ` Alan Stern
2019-06-07 15:05 ` Andrey Konovalov
2019-06-18 13:31 ` Andrey Konovalov
2019-06-18 13:34 ` Andrey Konovalov
2019-06-18 13:53 ` Alan Stern
2019-06-19 6:36 ` Felipe Balbi [this message]
2019-06-28 16:44 ` Andrey Konovalov
2019-06-28 17:29 ` Andrey Konovalov
2019-06-28 18:07 ` Alan Stern
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