From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <4D63DA2C.3020104@bouyapop.org> Date: Tue, 22 Feb 2011 16:45:48 +0100 From: Philippe Anel User-Agent: Mozilla/5.0 (Windows; U; Windows NT 6.1; fr; rv:1.9.2.13) Gecko/20101207 Thunderbird/3.1.7 MIME-Version: 1.0 To: 9fans@9fans.net References: <20110222151218.4A02965D3E@server.hemiola.co.uk> <4D63D6D4.5040808@bouyapop.org> In-Reply-To: <4D63D6D4.5040808@bouyapop.org> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [9fans] usb ohci question Topicbox-Message-UUID: b2db8fbc-ead6-11e9-9d60-3106f5b1d025 Oh, sorry, I forgot that the page-in operation might require an interrupt from the disk or network controller in order to reload the page. Phil; Le 22/02/2011 16:31, Philippe Anel a �crit : > Hello, > > A 'page-in' occurs on page fault exception, which cannot be masked. > > Phil; > > > Le 22/02/2011 16:10, rod@hemiola.co.uk a �crit : >> I'm struggling to understand the ins and outs of the usb ohci driver >> (usbohci.c) and have a question (well, several). >> >> If one writes to an endpoint, then "epio" gets called. This in turn >> does ilock(ctrl) which disables interrupts on my single-processor >> machine. Then "epgettd" is called several times to allocate transfer >> descriptors. Each call to epgettd copies a portion from the user space >> buffer which was passed as a parameter to "epio". >> >> What happens here if the user space buffer is in a page which is not >> present? Is it possible for a page-in to happen even when interrupts >> are disabled by the ilock? >> >> Thanks for any insight. >> >> rod >> >> > > >