On Mon, Aug 15, 2011 at 09:34:23PM -0700, Ping Cheng wrote: > On Sun, Aug 14, 2011 at 8:27 PM, Chris Bagwell <chris@xxxxxxxxxxxxxx> wrote: > > > On Fri, Aug 12, 2011 at 7:08 PM, Ping Cheng <pinglinux@xxxxxxxxx> wrote: > > > Touch devices do not report valid pressure or capacitance. > > > > > > Signed-off-by: Ping Cheng <pingc@xxxxxxxxx> > > > --- > > > > I'd prefer if we kept pressure support. At least for Bamboo's with > > product ID between 0xd0 and 0xd4. > > > > In my testing of an 0xd1 device, pressure works fine (low pressure and > > high pressure work great. Not much middle pressure sensitivity. > > Multi-touch will increase pressure reading. All pretty common > > behaviour). > > > > Basically, there were three reasons to remove the pressure bit for all touch > devices: > > 1. The value is not a pressure and it does not report valid capacitance > either; > 2. The only valid use in the kernel driver is to decide if the finger is > touching the tablet or not, which has already been correctly reported by the > firmware in the other bits. So, it is redundant to check the pressure for > this purpose; > 3. Passing the invalid "pressure" to the user land would only introduce > bad user experience since touch is not designed for drawing. We don't want > to confuse user with that "pressure". Not speaking about touch per se, but pressure is important for other things besides drawing. Different people prefer different device sensitivity and if userspace knows pressure it can adjust according to user preference, like synaptics X driver does with touchpads that actually report it. I believe tslib allows similar for touchscreens. 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
