From: Hans Petter Selasky <hselasky@c2i.net>
To: linux-media@vger.kernel.org
Subject: Question about V4L2_MEMORY_USERPTR
Date: Fri, 23 Mar 2012 08:19:45 +0100 [thread overview]
Message-ID: <201203230819.45385.hselasky@c2i.net> (raw)
Hi,
I have a question about V4L2_MEMORY_USERPTR:
>From which context are the kernel's "copy_to_user()" functions called in
relation to V4L2_MEMORY_USERPTR ? Can this be a USB callback function or is it
only syscalls, like read/write/ioctl that are allowed to call "copy_to_user()"
?
The reason for asking is that I am maintaining a userland port of the media
tree's USB drivers for FreeBSD. At the present moment it is not allowed to
call copy_to_user() or copy_from_user() unless the backtrace shows a syscall,
so the V4L2_MEMORY_USERPTR feature is simply removed and disabled. I'm
currently thinking how I can enable this feature.
--HPS
next reply other threads:[~2012-03-23 7:32 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-23 7:19 Hans Petter Selasky [this message]
2012-07-01 14:00 ` Question about V4L2_MEMORY_USERPTR Sakari Ailus
2012-07-02 9:24 ` Laurent Pinchart
2012-07-02 19:07 ` Hans Petter Selasky
2012-07-05 17:24 ` Laurent Pinchart
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