Hi Sakari and Luca, On Sun, Aug 26, 2018 at 10:41:13PM +0200, Luca Ceresoli wrote: > Hi Sakari, > > On 25/08/2018 16:49, Sakari Ailus wrote: > > Hi Luca, > > > > On Fri, Aug 24, 2018 at 06:35:21PM +0200, Luca Ceresoli wrote: > >> Forcibly setting the subdev name to DRIVER_NAME (i.e. "IMX274") makes > >> it non-unique and less informative. > >> > >> Let the driver use the default name from i2c, e.g. "IMX274 2-001a". > >> ... > > > > This ends up changing the entity as well as the sub-device name which may > > well break applications. > > Right, unfortunately. > > > On the other hand, you currently can't have more > > than one of these devices on a media device complex due to the name being > > specific to a driver, not the device. > > > > An option avoiding that would be to let the user choose by e.g. through a > > Kconfig option would avoid having to address that, but I really hate adding > > such options. > > I agree adding a Kconfig option just for this would be very annoying. > However I think the issue affects a few other drivers (sr030pc30.c and > s5c73m3-core.c apparently), thus maybe one option could serve them all. > > > I wonder what others think. If anyone ever needs to add another on a board > > so that it ends up being the part of the same media device complex > > (likely), then changing the name now rather than later would be the least > > pain. In this case I'd be leaning (slightly) towards accepting the patch > > and hoping there wouldn't be any fallout... I don't see any board (DT) > > containing imx274, at least not in the upstream kernel. > > I'll be OK with either decision. Should we keep it as is, then I think a > comment before that line would be appropriate to clarify it's not > correct but it is kept for backward userspace compatibility. This would > help avoid new driver writers doing the same mistake, and prevent other > people to send another patch like mine. Would it be acceptable to accept Luca's patch but add a dev_info message indicating the old and the new name, so that at least if the user notices a problem he'll find an informative message helping him to fix his config ? This dev_info message could even be standardized to be usable for other drivers with only the names changed. Philippe -- Philippe De Muyter +32 2 6101532 Macq SA rue de l'Aeronef 2 B-1140 Bruxelles
