On Fri, Jan 28, 2011 at 11:12 AM, Henrik Rydberg <rydberg@xxxxxxxxxxx> wrote: >> >> This is mainly required by the serial pen and touch devices since >> >> both pen and touch are on the same port. Updated the USB ones to >> >> keep MT event definition consistent among serial and USB devices. >> > >> > Why is this change performed? What does the patch do? Please elaborate >> > a little bit. >> >> Let's see if I can explain it clearer or not. >> >> We need to report resolution to userland for wacom_w8001.c. > > Thanks, perfect - sentences like this one is great to put in the patch > description. Thanks for the encouragement ;). >> Since pen >> and touch data are reported through the same logical port for serial >> devices, using input_abs_set_res for ABS_X/Y, we can only pass the >> resolution for pen or touch. So, I let ABS_X/Y report pen resolution >> since most legacy ST clients process pen data over touch. However, for >> multi-touch clients, especially for those that support gestures, touch >> resolution is needed to calculate the physical distance between two >> touch points. Using ABS_MT_POSITION_X/Y does not cause confusion and >> it is quite intuitive. > > I thought this was solved by reporting both pen and touch on the same > scale, which would render this problem moot. Or? Yeah, see my reply to Dmitry for detail. > [...] >> > Is this for the BAMBOO_PT case? What about the extra x/y scaling for >> > some of those devices? >> >> Yes, it is for Bamboo. We do not need to scale the value here since >> touch and pen are on different ports. We had to scale the value for >> wacom_w8001 since both pen and touch are on the same port. Without >> scaling the data, the pen/finger tip will not follow the cursor on the >> screen (wacom_w8001 is a touchscren device). > > I was thinking of the scaling quirk in effect for the Bamboo > Touch. The resolution would have to change as well. Yes, If we need to report the right values ;). Ping -- 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
