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Date: Sat, 11 Jun 2011 00:46:06 +0300
From: Felipe Balbi <balbi@ti.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Felipe Balbi <balbi@ti.com>,
	Theodore Kilgore <kilgota@banach.math.auburn.edu>,
	Hans de Goede <hdegoede@redhat.com>,
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Subject: Re: Improving kernel -> userspace (usbfs)  usb device hand off
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Hi,

On Fri, Jun 10, 2011 at 05:18:39PM -0400, Alan Stern wrote:
> > > 2. Until recently in the history of Linux, there was an irreconcilabl=
e=20
> > > conflict. If a kernel driver for the video streaming mode was present=
 and=20
> > > installed, it was not possible to use the camera in stillcam mode at =
all.=20
> > > Thus the only solution to the problem was to blacklist the kernel mod=
ule=20
> > > so that it would not get loaded automatically and only to install sai=
d=20
> > > module by hand if the camera were to be used in video streaming mode,=
 then=20
> > > to rmmod it immediately afterwards. Very cumbersome, obviously.=20
> >=20
> > true... but why couldn't we combine both in kernel or in userspace
> > altogether ? Why do we have this split ? (words from a newbie in V4L2,
> > go easy :-p)
>=20
> I think the problem may be that the PTP protocol used in the still-cam
> mode isn't suitable for a kernel driver.  Or if it is suitable, it
> would have to be something like a shared-filesystem driver -- nothing
> like a video driver.  You certainly wouldn't want to put it in V4L2.

ach true.. Had forgotten that detail. Needs more thinking.

--=20
balbi

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