Em 01-06-2011 10:27, Hans Verkuil escreveu: >> Hi Hans, >> >> Em 23-05-2011 08:15, Hans Verkuil escreveu: >>> Hi Mauro, >>> >>> These patches for 2.6.41 add support for bitmask controls, needed for >>> the >>> upcoming Flash API and HDMI API. >> >> DocBook changes need do a s/2.6.41/3.1/. > > Of course, I saw your DocBook changes going today. Btw, you may need to adjust your daily scripts, as the patches changed the place where the V4L API is placed. >> That's said, I'm not sure if it is a good idea to add bitmask type, >> instead of >> just using a set of boolean controls. > > There are currently two use cases: Sakari's flash controller needs to > report errors which are a bitmask of possible error conditions. It is way > overkill to split that up in separate boolean controls, especially since > apps will also want to get an event whenever such an error is raised. Hmm... returning errors via V4L2 controls don't seem to be a good implementation. I need to review his RFC to better understand his idea. > The other is in HDMI receivers where there can be multiple ports that do > EDID handling, but only one can stream. You need a way to tell which ports > received an EDID for example. Again, you can make multiple boolean > controls like HDMI_PORT0_EDID_REC, PORT1, PORT2, PORT3, etc. but that is a > waste of code and time. Ok, this seems to be a good example. >> One of the issues with bitmasks is >> the >> endness type: LE, BE or machine endianness. The specs don't mention how >> this >> is supposed to work. > > Good point. It's machine endianness, but that definitely has to be > documented. I'll do that. OK, thanks! >> Also, I'd like to see a patch like that submitting with a driver or >> feature >> that needs it. Before you ask: no, vivi doesn't count ;) > > Sakari will hopefully be the first 'real' user for this for a flash driver. Thanks, 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
