Re: questions about the internal of the driver
Michel Xhaard <[email protected]>
| Newsgroups | gmane.linux.drivers.spca50x.devel |
|---|---|
| Message-ID | <[email protected]> |
Le dimanche 3 février 2008 11:59, Jean-Francois Moine a écrit : Jean François, > When I wrote some code for the v2l version 2, I found the grabbing > frame state is not clear. I think that an other state should be > required meaning the frame is treated by the application. > > Then, I was wondering why is there a tasklet do to the conversion. > In other drivers such as ov51x-jpeg, Don't really know ov51x-jpeg sorry :( > the conversion is done by the > application. So, the code may be simpler: The gspcav1 is v4l1, v4l1 know nothing about mjpeg that is why a tasklet is used here. > > - receiving iso packets, move the data to the frame buffer, state > GRABBING. > - when end of frame (start of new frame) is detected, change the > state to READY (and that's all). > - when the application asks for a new frame (read() or iotcl() > VIDIOCMCAPTURE or VIDIOC_DQBUF), convert the frame to the > desired palette and change the state to DONE. > - when the application releases the frame (end of read() or ioctl() > VIDIOCSYNC or VIDIOC_QBUF, free the buffer setting its state > to UNUSED. > > Doing so should avoid the problem occuring with 2 frame buffers: > - one buffer being grabbed, > - this other one being converted and > - which one being processed by the application... Interresting. My firs idea was to stop developping gspcav1 and start a new branch for v4l2 support. http://mxhaard.free.fr/spca50x/Investigation/Gspca/ http://linuxtv.org/hg/~mchehab/gspca/ The problem is no one seem interresting to develop this branch, of course it is difficult as we need to be sure the > 270 webcam are ok after each small change ;-) I see you change the core driver to add your chipset.I have to double check all webcams are working before apply, sorry for the delay bests regards -- Michel Xhaard http://mxhaard.free.fr ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Spca50x-devs mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/spca50x-devs