On Sun, 29 Mar 2009 11:06:19 +0200 Hans Verkuil <hverkuil@xxxxxxxxx> wrote: > On Sunday 29 March 2009 10:50:02 Patch from Trent Piepho wrote: > > The patch number 11260 was added via Trent Piepho <xyzzy@xxxxxxxxxxxxx> > > to http://linuxtv.org/hg/v4l-dvb master development tree. > > > > Kernel patches in this development tree may be modified to be backward > > compatible with older kernels. Compatibility modifications will be > > removed before inclusion into the mainstream Kernel > > > > If anyone has any objections, please let us know by sending a message to: > > Linux Media Mailing List <linux-media@xxxxxxxxxxxxxxx> > > > > ------ > > > > From: Trent Piepho <xyzzy@xxxxxxxxxxxxx> > > v4l2-ioctl: Check format for S_PARM and G_PARM > > > > > > Return EINVAL if VIDIOC_S/G_PARM is called for a buffer type that the > > driver doesn't define a ->vidioc_try_fmt_XXX() method for. Several other > > ioctls, like QUERYBUF, QBUF, and DQBUF, etc. do this too. It saves each > > driver from having to check if the buffer type is one that it supports. > > Hi Trent, > > I wonder whether this change is correct. Looking at the spec I see that > g/s_parm only supports VIDEO_CAPTURE, VIDEO_OUTPUT and PRIVATE or up. > > So what should happen if the type is VIDEO_OVERLAY? I think the g/s_parm > implementation in v4l2-ioctl.c should first exclude the unsupported types > before calling check_fmt. Makes sense to me. > I also wonder whether check_fmt shouldn't check for the presence of the > s_fmt callbacks instead of try_fmt since try_fmt is an optional ioctl. One developer suggested to merge try_fmt and s_fmt into one callback. IMO, this makes sense, since I have the feeling that this will simplify the code a little bit on the drivers. If we go this way, then we can check for the new try_s_fmt callback. Cheers, Mauro -- 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
