Mauro Carvalho Chehab wrote: > Michael Krufky wrote: >> On Fri, Dec 4, 2009 at 3:02 PM, VDR User <user.vdr@xxxxxxxxx> wrote: >>> No activity in this thread for 2 weeks now. Has there been any progress? > >> I have stated that I like Manu's proposal, but I would prefer that the >> get_property (s2api) interface were used, because it totally provides >> an interface that is sufficient for this feature. > > I've ported Manu's proposal to S2API way of handling it. It is just compiled > only. I haven't test it yet on a real driver. > > Comments? > > --- > > Add support for frontend statistics via S2API > > The current DVB V3 API to handle statistics has two issues: > - Retrieving several values can't be done atomically; > - There's no indication about scale information. > > This patch solves those two issues by adding a group of S2API > that handles the needed statistics operations. It basically ports the > proposal of Manu Abraham <abraham.manu@xxxxxxxxx> To S2API. > > As the original patch, both of the above issues were addressed. > > In order to demonstrate the changes on an existing driver for the new API, I've > implemented it at the cx24123 driver. > > There are some advantages of using this approach over using the static structs > of the original proposal: > - userspace can select an arbitrary number of parameters on his get request; > - the latency to retrieve just one parameter is lower than retrieving > several parameters. On the cx24123 example, if user wants just signal strength, > the latency is the same as reading one register via i2c bus. If using the original > proposal, the latency would be 6 times worse, since you would need to get 3 properties > at the same time; > - the latency for reading all 3 parameters at the same time is equal to > the latency of the original proposal; > - if newer statistics parameters will be needed in the future, it is just > a matter of adding additional S2API command/value pairs; > - the DVB V3 calls can be easily implemented as a call to the new get_stats ops, > without adding extra latency time. In time: I only wrote the get callback. It could be interesting to implement also the set callback for the DTV_FE*_UNIT parameters if there are some cases where the same driver can provide a different set of units/parameters. This way, it is possible for userspace to negotiate what parameter type he wants, on such drivers. > > Thanks to Manu Abraham <abraham.manu@xxxxxxxxx> for his initial proposal. > 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
