On Wed, 19 Jan 2005 15:16:08 +0100, Hannes Reinecke <[EMAIL PROTECTED]> wrote: > Dmitry Torokhov wrote: > > Hi Hannes, > > > > On Wed, 19 Jan 2005 10:59:30 +0100, Hannes Reinecke <[EMAIL PROTECTED]> > > wrote: > > > >>Dmitry Torokhov wrote: > >> > >>>But the real question is whether we really need class devices have > >>>unique names or we could do with inputX thus leaving individual > >>>drivers intact and only modifying the input core. As far as I > >>>understand userspace should be concerned only with device > >>>capabilities, not particular name, besides, it gets PRODUCT string > >>>which has all needed data encoded. > >>> > >> > >>Indeed. What about using 'phys' (with all '/' replaced by '-') as the > >>class_id? This way we'll retain compability with /proc/bus/input/devices > >>and do not have to touch every single driver. > >> > > > > > > I want to kill phys at some point - we have topology information > > already present in sysfs in much better form. Can we have a new > > hotplug variable HWDEV= which is kobject_path(input_dev->dev). If > > input_dev is not set then we can just dump phys in it. And the class > > id will still be inputX. Will this work? > > > Sure. And we don't need a special HWDEV variable, as there is already a > PHYSDEVPATH variable providing exactly this information.
Oh right! Even better. > I'm not too happy about this 'inputX' thing (as this doesn't carry any > information, whereas 'phys' gives you at least a rough guess what this > device's about), but if phys is to go it would be the logical choice. > The problem with encoding phys in class ID is the following: you have to guarantee that the moment you destroy underlying hw device yur input_device has to be gone too. Imagine you have input_device for your PS/2 mouse and you decide to unload psmouse module. You also have one of user processes holding any of the class device attributes open. This causes input_device to be pinned into memory so when you load psmouse module back again it will not be able to create new input_device and mouse will be dead. With monotonicaly increasing inputX name you will never have this issue. You had a workaround for this problem with your original path but when you fold it all in core you lost it. -- Dmitry - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
