Mailing List Archive: Re: V4L: Black and white quickcam enhancement

> 1. Fix for missing camera parameter update if the grab size is
> changed with VIDIOCSWIN.
Ok
> 3. Addition of parameters to control the frequency of yields to the
> scheduler when grabbing a frame from the quickcam. This should
> avoid having 'freezes' for 1-2 seconds while a frame is grabbed.
Nice
> Todo:
>
> 1. Memory-mapped grabbing support.
Don't bother. Its not something that you gain by doing - the device
isnt memory mapped or DMA capable.
> 3. SMP protection ??
It should be ok SMP - it could be more polite thats all
> 4. Camera detection scheme improvements?
I'm still trying to find a better scheme - the qcam never had a detect
scheme.
Alan
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On Sat, 23 Jan 1999, Alan Cox wrote:
> Date: Sat, 23 Jan 1999 22:38:17 +0000 (GMT)
> To: Mark Cooke <mpc@star.sr.bham.ac.uk>
>
> > 3. Addition of parameters to control the frequency of yields to the
> > scheduler when grabbing a frame from the quickcam. This should
> > avoid having 'freezes' for 1-2 seconds while a frame is grabbed.
>
> Nice
I'd about had it with my new box freezing up for longer than my P166
used to. I finally made time to scratch the itch ;-)
The downside is that I can't tell as easily when people are looking at
the web-camera in my office and I need to smile for 'em (or look busy
for my boss) *winks*
> > Todo:
> >
> > 1. Memory-mapped grabbing support.
>
> Don't bother. Its not something that you gain by doing - the device
> isnt memory mapped or DMA capable.
The only thing is compatability with some existing V4L supporting
software that doesn't grok read(). It's not a high priority here, and
it's taken me nearly 2 months to make time to make these small
changes ;-)
> > 3. SMP protection ??
>
> It should be ok SMP - it could be more polite thats all
Any quick pointers on this? (Pointer to parts of other drivers that
are 'nicer' would be great). I'm going to add a second CPU to this P2
soon, so I will have some (minor) incentive to improve things here.
> > 4. Camera detection scheme improvements?
>
> I'm still trying to find a better scheme - the qcam never had a detect
> scheme.
Aye. Oh...Didn't mention in the first mail - the patch stretched the
detection limits slightly. Just enough to be (mostly) detected on my
machine first time.
I half considered adding a 'passive' module flag, that would let you
toggle between the current scheme, and the potentially printer
breaking Connectix scheme (reset and try to handshake). I don't have a
printer hooked up though, so it's on the 'possibly nice to make time
for' pile.
I guess I missed '5. V4L2 compatability' too.
Best Regards,
Mark
+-------------------------------------------------------------------------+
Mark Cooke The views expressed above are mine and are not
Systems Programmer necessarily representative of university policy
University Of Birmingham URL: http://www.sr.bham.ac.uk/~mpc/
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