On Thu, May 24, 2012 at 10:33:49AM -0700, Linus Torvalds wrote: > On Thu, May 24, 2012 at 1:32 AM, Dmitry Torokhov > <dmitry.torokhov@xxxxxxxxx> wrote: > > Hi Linus, > > > > to receive updates for the input subsystem. You will get: > > I get an annoying conflict, and the reason I call it annoying is not > because it's hard to resolve, it's because doing that shows that you > seem to have preferred using > > dev_dbg(&input->dev.parent, ...) > > over the much more natural > > dev_dbg(&input->dev, ...) > > which would seem to make more sense. > > Why? Are the input layer device names so bad that using them for debug > output is useless? And if so, why *are* they so bad? > > I'm going to take your version over Greg's more straightforward one, > because I assume Greg did things a bit more mindlessly and I think you > presumably had a *reason* for your extra (stupid) ".parent" part. But > I'm unhappy with it, because I suspect the reason you did that implies > that the input layer does something bad. A couple of points: 1. A driver should try to use the same device for all its messages and input devices are not created yet at the time we try to bind USB interface to a driver. Most (all?) USB probe() methods use interface's device with dev_xxx() which shows exactly which interface we are dealing with. 2. Input devices are essentially driver-less (they are class devices) and therefore do not provide useful information if used in messages as the format of the message would be: input inputX: some message which does not identify neitehr the driver nor hardware device. By using input->dev.parent we get to the USB interface thus getting more meaningful messages: wacom 2-1.2:1.0: some error happened We had a discussion with Greg about this and he was going to change his patchset to use USB interfaces in the messages... Thanks. -- Dmitry -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
