From: rod@hemiola.co.uk
To: 9fans@9fans.net
Subject: [9fans] usb ohci question
Date: Tue, 22 Feb 2011 15:10:12 +0000 [thread overview]
Message-ID: <20110222151218.4A02965D3E@server.hemiola.co.uk> (raw)
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
next reply other threads:[~2011-02-22 15:10 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-02-22 15:10 rod [this message]
2011-02-22 15:30 ` Francisco J Ballesteros
2011-02-22 16:42 ` rod
2011-02-22 16:50 ` Francisco J Ballesteros
2011-02-22 15:31 ` Philippe Anel
2011-02-22 15:45 ` Philippe Anel
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