On Thu July 19 2012 21:55:20 Ezequiel Garcia wrote: > On Thu, Jul 19, 2012 at 4:48 PM, Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > > On Thu July 19 2012 20:41:11 Ismael Luceno wrote: > >> On Thu, 19 Jul 2012 10:25:09 -0300 > >> Ezequiel Garcia <elezegarcia@xxxxxxxxx> wrote: > >> > On Wed, Jul 18, 2012 at 7:26 PM, Ismael Luceno > >> > <ismael.luceno@xxxxxxxxx> wrote: > >> > > On Thu, Jun 21, 2012 at 4:52 PM, Ezequiel Garcia > >> > > <elezegarcia@xxxxxxxxx> wrote: > >> > >> This patch moves video_nr module parameter to core.c > >> > >> and then passes that parameter as an argument to functions > >> > >> that need it. > >> > >> This way we avoid the extern declaration and parameter > >> > >> dependencies are better exposed. > >> > > <...> > >> > > > >> > > NACK. > >> > > > >> > > The changes to video_nr are supposed to be preserved. > >> > > >> > Mmm, I'm sorry but I don't see any functionality change in this patch, > >> > just a cleanup. > >> > > >> > What do you mean by "changes to video_nr are supposed to be > >> > preserved"? > >> > >> It is modified by solo_enc_alloc, which is called multiple times by > >> solo_enc_v4l2_init. > > > > You don't need to modify it at all. video_register_device() will start > > looking for a free video node number starting at video_nr and counting > > upwards, so increasing video_nr has no purpose. Leaving it out will give > > you exactly the same result. > > > > Yes, but perhaps the module author wanted to force a device > /dev/videoX *start* number, > as it's documented in the parameter usage string: > > MODULE_PARM_DESC(video_nr, "videoX start number, -1 is autodetect (default)"); > > Now, I don't now why would one want to do that or if it makes sense at all. > In any case, it seems it's the intended behavior. > But doing video_nr++ is pointless and will not have an effect. Example: if video_nr is specified as 2, then video_register_device() will attempt to make a /dev/video2 node, if that's already in use, then it will try /dev/video3, etc. So doing video_nr++ after a video_register_device() will not change the outcome for the next video_register_device() that is called, and has the somewhat odd side-effect of changing the video_nr module parameter from what the user passed in. So cat /sys/module/vivi/parameters/video_nr returns 3 instead of 2. Just don't change it and let video_register_device() do its magic. Regards, Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
