On 2011-10-27, at 1:44 AM, Dmitry Torokhov wrote: > On Wed, Oct 26, 2011 at 05:10:23PM -0400, Dwayne Litzenberger wrote: >> Let's say I have a touchscreen, and I move my finger to (200,100). >> I'll see something line this (simplified): >> >> EV_ABS ABS_X 200 >> EV_ABS ABS_Y 100 >> EV_SYN >> >> Next, let's say I see something like this: >> >> EV_ABS ABS_Y 90 >> EV_SYN >> >> What is the meaning of that, from the perspective of userspace? >> I see two possibilities. Either: >> >> 1. It's a move to (200,90), or >> 2. It's a move to (0,90) >> >> Which is the correct interpretation? > > Door #1. > >> Is this documented anywhere? > > From Documentation/input/event-codes.txt: > > "The input protocol is a stateful protocol. Events are emitted only when > values of event codes have changed. However, the state is maintained > within the Linux input subsystem; drivers do not need to maintain the > state and may attempt to emit unchanged values without harm. Userspace > may obtain the current state of event code values using the EVIOCG* > ioctls defined in linux/input.h." > >> >> Apparently, the usbhid driver is generating events that imply #1, but >> xserver-xorg-input-evdev interprets these according to #2. I'm trying >> to figure out what needs to be patched. :) > > xserver-xorg-input-evdev. Awesome. That's exactly what I need. Thanks! - Dwayne -- 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
