questions about the internal of the driver
Jean-Francois Moine <[email protected]>
| Newsgroups | gmane.linux.drivers.spca50x.devel |
|---|---|
| Message-ID | <TTY-Grin-jef-47A59E97.57BD9693@jef> |
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, the conversion is done by the application. So, the code may be simpler: - 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... -- Ken ar c'hentañ | ** Breizh ha Linux atav! ** Jef | http://moinejf.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