On Wed, Mar 06, 2013 at 11:02:47AM +0100, Hans Verkuil wrote: > On Wed 6 March 2013 10:48:13 volokh84@xxxxxxxxx wrote: > > Hi, > > Hans > > > > I found in d8077d2df184f3ef63ed9ff4579d41ca64e12855 commit, > > that V4L2_CTRL_FLAG_VOLATILE flag was disabled for some STD controls > > and fully disabled g_ctrl iface. So How can userspace know about changing some values? > > VOLATILE is used when register values can change automatically (e.g. if > autogain is on and the device regulates the gain and updates that gain > register itself). > Right that!!! there one register for all 4 channell for each of AUTOGAIN,CHROMA,RED_B,BLUE_B reg, so if one channel changes CHROMA value (it changes all 4 channels), the another channel will have cached old value, instead new (case it value have not volatile control) > However, testing proved that the hardware doesn't update anything when > in autogain mode, hence volatile support isn't needed. > > Note that the control framework always caches the last control value, > so to get non-volatile controls the framework just returns that cached > value. > > 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 > -- 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
