Re: [libdc1394-devel] speedup format 7 controls

[<T....@go...>]

The offset is the general format7 offset, and i implemented  it on a per=20
camera(/node) basis, not per f7-mode
dcam specs a maximum of 16 Cameras, thats why 16.
as the chache is filled in set=5Ff7... the correct value for the requested =

mode is stroed ther, no need to store the other offset i think.
I agrre, that the dc913=5Fcamerahandle  is a good place to take care of=20
this. i will send a new patch with that soon.


but now i am confuse. I work on libdc version 9.1.0 and cannot find any=20
dc1394=5Fcamerhandle. all i see is dc1394=5Fhandle, which is the handle for=
 a=20
whole port.
As i use only one Firewire Card, I have 2 Cameras on this port attached.=20
Didnt you meant the cmera=5Finfo structure as a place for the cache?

--=20
Mit freundlichen Gr=FC=DFen,
Dipl.-Ing. Tim Evers
GOM mbH
Braunschweig, Deutschland=20
(www.gom.com)




Damien Douxchamps <d.d...@te...>
Sent by: lib...@li...
15/01/2004 16:33

=20
        To:     T....@go...
        cc:     libdc1394-devel <lib...@li...>
        Subject:        Re: [libdc1394-devel] speedup format 7 controls


Hi Tim,

On Thu, 2004-01-15 at 14:22, T....@go... wrote:
> In my experience with the libdc1394 format7 commands I found that every=20
> command that accesses the format 7 CSR is looking up the address-offset=20
> first.
> As this offset isn't chanign during the operation, i suggest a caching=20
of=20
> this offset for each camera.
> I append a patch, wich does that, the chache is cleard in=20
> =5Fdc1394=5Fbasic=5Fformat7=5Fsetup because it is imhop the easiest way t=
o=20
handle=20
> different camera types. A detection of a node-change would be nicer=20
> though.
>=20
> please tell me you thoughts, and if this patch has a chance to go in.

It's a good idea to cache this kind of information (as it is static on a
camera basis), but it should go in dc1394=5Fcamerahandle. Filling the
offsets is then the task of dc1394=5Fget=5Fcamera=5Finfo. IMHO if you defin=
e a
global variable it becomes really messy for mutliple camera operation.

Also, why do you define 16 offsets below, while there is only 8 modes in
format7?

+#ifdef CACHE=5FF7=5FOFFSET
+quadlet=5Ft format7=5Fcsr=5Foffset[16]=3D{0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
+#endif

Damien

--=20
  =5F    Damien Douxchamps
 (=B0-   PhD Student / Research Assistant
 //\   Image Processing Group, Telecom Laboratory, UCL, Belgium
 V=5F/=5F  http://www.tele.ucl.ac.be/MEMBERS/Douxchamps=5FDamien=5Fe.html




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