Date: Thu, 27 Feb 2014 08:09:45 +0100 From: Hans Petter Selasky <hps@bitfrost.no> To: Kohji Okuno <okuno.kohji@jp.panasonic.com>, freebsd-current@freebsd.org Subject: Re: kqueue for usb_dev Message-ID: <530EE4B9.6080605@bitfrost.no> In-Reply-To: <20140227060232.GA47921@funkthat.com> References: <20140227.142615.924807465819500067.okuno.kohji@jp.panasonic.com> <20140227060232.GA47921@funkthat.com>
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On 02/27/14 07:02, John-Mark Gurney wrote: > 2) Why do you try to start read/write transfers in the _filter? You > should just check to see if data is available and not do work.. This > is also important since kqueue calls the filter just before delivering > the knote to userland to verify that there is still data, and it will > call your _event function for each knote on the fd... The work should > be started through other mechanisms, like read/write syscall or > interrupt or timeout/callout... If it's required to get results from > USB_IF_POLL, then it's fine.. Hi, In the case where you start polling and don't do any reads or writes, the poller needs to get the data traffic going. --HPS
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