Hi Guennadi, > Hi Detlev > > On Fri, 24 Aug 2012, Detlev Zundel wrote: > >> Hello Guennadi, >> >> > Hi Anatolij >> > >> > On Fri, 24 Aug 2012, Anatolij Gustschin wrote: >> > >> >> Add controls for horizontal and vertical blanking, analog control >> >> and control for undocumented register 32. >> > >> > Sorry, I don't think this is a good idea to export an undocumented >> > register as a control. >> >> Why exactly is that? Even though it is not documented, we need to >> fiddle with it to make our application work at all. So we tend to >> believe that other users of the chip will want to use it also. > > Below I asked to provide details about how you have to change this > register value: toggle dynamically at run-time or just set once at > initialisation? Even if toggle: are this certain moments, related to > standard camera activities (e.g., starting and stopping streaming, > changing geometry etc.) or you have to set this absolutely asynchronously > at moments of time, that only your application knows about? Anatolij can answer those detail questions, all I know is that without fiddling with the register we do not receive valid pictures at all. >> Furthermore I don't see that we fundamentally reject patches for other >> parts in the Linux kernel where people found out things not in the >> official datasheets. > > The problem is not, that this register is undocumented, the problem rather > is, that IMHO exporting an API to user-space, setting an undocumented > register to arbitrary values is, hm, at least pretty dubious. As I wrote above, without fiddling with the register, we do _not_ receive correct pictures at all. So this is not dubious but shown by experiment to be needed (at least in our setup). Best wishes Detlev -- A language that doesn't affect the way you think about programming, is not worth knowing. -- Alan Perlis, Epigrams on Programming -- 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
