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From: "Baxter, Jim" <jim_baxter@mentor.com>
To: Robert Baldyga <r.baldyga@samsung.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
	"Zapolskiy, Vladimir" <Vladimir_Zapolskiy@mentor.com>,
	"balbi@ti.com" <balbi@ti.com>
Subject: Re: usb: gadget: f_fs: O_NONBLOCK waits MAX_SCHEDULE_TIMEOUT
Date: Wed, 1 Apr 2015 18:29:05 +0100	[thread overview]
Message-ID: <551C2AE1.9000608@mentor.com> (raw)
In-Reply-To: <551BA70B.1090706@samsung.com>

> 
> FunctionFS is very specific, because read/write operations are directly
> translated into USB requests, which are asynchronous, so you cannot use
> O_NONBLOCK.
> 
> If you need non-blocking API you can use Asynchronous I/O (AIO). You can
> find some examples in kernel sources (tools/usb/ffs-aio-example/).
> 
> Br,
> Robert Baldyga
> 

Thank you, that sounds like the best approach.
In this case I think perhaps the long wait without any data is an
problem with the imx6 Chipidea USB controller.

I guess it should suspend and drop the connections if there is no
traffic for more than 10ms?

Thanks.
Jim Baxter

  reply	other threads:[~2015-04-01 17:29 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-31 18:53 usb: gadget: f_fs: O_NONBLOCK waits MAX_SCHEDULE_TIMEOUT Baxter, Jim
2015-03-31 20:28 ` Felipe Balbi
2015-04-01  8:06 ` Robert Baldyga
2015-04-01 17:29   ` Baxter, Jim [this message]
2015-04-02  0:23     ` Peter Chen
2015-05-22 11:12       ` Baxter, Jim
2015-05-25  1:55         ` Peter Chen
2015-06-01 16:25           ` Baxter, Jim
2015-06-02  3:01             ` Peter Chen

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