On 03/22/2015 01:38 PM, Laurent Pinchart wrote: > Hi Hans, > > Thank you for the patch. > > On Friday 20 March 2015 13:17:19 Hans Verkuil wrote: >> The descriptions used in drivers for the formats returned with ENUM_FMT >> are all over the place. >> >> So instead allow the core to fill in the description and flags. This >> allows drivers to drop the description and flags. >> >> If the format is not found in the list, and if the description field is >> filled in, then just return but call WARN_ONCE to let developers know >> that this list needs to be extended. >> >> Based on an earlier patch from Philipp Zabel: >> http://comments.gmane.org/gmane.linux.drivers.video-input-infrastructure/814 >> 11 >> >> But this patch moves the code into the core and away from drivers. >> >> Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx> >> Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> > > I have a similar patch in one of my git trees, although I'm not sure exactly > where I've put it :-) It at least means that I like the idea. > > Acked-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > > I wonder whether the big switch statement could be optimized though, > especially given that there's two of them, one for the description, and one > for the flags. You could store the information in an array and lookup the > entry based on the pixelcode, that would at least get rid of one switch > statement. Further optimization would be possible by using some kind of hash > table, but I'm not sure if it's worth it. The gcc compiler is quite smart when optimizing a switch statement, it certainly produces code that is faster than a table lookup. I'll take a look at the gcc output, but I expect it to be either O(log N) comparisons, or possibly even O(1) if it is smart enough to create a perfect hash for this. 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
