On Thu, Oct 11, 2018 at 11:09:49AM +0200, Hans de Goede wrote: > Hi, > > On 11-10-18 02:52, Dmitry Torokhov wrote: > > Hi Hans, > > > > Sorry, now I was being slow as well. > > No problem. > > > On Thu, Sep 20, 2018 at 07:31:43PM +0200, Hans de Goede wrote: > > > Hi, > > > > > > I completely missed this mail earlier, sorry. > > > > > > Thank you Benjamin for pointing this out to me. > > > > > > On 03-08-18 02:31, Dmitry Torokhov wrote: > > > > Hi Hans, > > > > > > > > On Tue, Jul 31, 2018 at 01:19:57PM +0200, Hans de Goede wrote: > > > > > Some touchscreens, depending on the firmware and/or the digitizer report > > > > > coordinates which never reach 0 along one or both of their axis. > > > > > > > > > > This has been seen for example on the Silead touchscreens on a Onda V891w > > > > > and a Point of View mobii TAB-P800w(v2.0). > > > > > > > > > > This commits documents 2 new touchscreen properties for communicating > > > > > the minimum reported values to the OS: touchscreen-min-x and -min-y. > > > > > > > > > > This commit also drop the (in pixels) comment from the documentation > > > > > of the touchscreen-size-x and touchscreen-size-y properties. This comment > > > > > suggests that there is a relation between the range of reported > > > > > coordinates and the display resolution, which is only true for some > > > > > devices. The (in pixels) comment is replaced with "(maximum x coordinate > > > > > reported + 1)" to mirror the language describing the new touchscreen-min-x > > > > > and -min-y properties. > > > > > > > > I am concerned that people will not read the documentation carefully and > > > > will treat it as true size, since it is what in the name. Maybe we > > > > should say that it is size of usable area, in device units, and that > > > > maximum reported coordinate is "touchscreen-min-x + touchscreen-size-x - > > > > 1"? > > > > > > Not sure what you mean with "true size" but in the implementation > > > from this series, the maximum coordinated reported is (touchscreen-size-x - 1) > > > not (touchscreen-min-x + touchscreen-size-x - 1) as you suggest. > > > > > > Basically what this series does is set: > > > > > > input_absinfo.minimum to the new touchscreen-min-x value (or 0 if not specified) > > > input_absinfo.maximum to touchscreen-size-x - 1 as we've always done. > > > > > > So the usable range / the range mapping from one screen edge to the other is: > > > > > > touchscreen-min-x - (touchscreen-size-x - 1) > > > > > > Which matches with the dt bindings doc after this patch, which > > > reads after this patch: > > > > > > - touchscreen-min-x : minimum x coordinate reported (0 if not set) > > > - touchscreen-min-y : minimum y coordinate reported (0 if not set) > > > - touchscreen-size-x : horizontal resolution of touchscreen > > > (maximum x coordinate reported + 1) > > > - touchscreen-size-y : vertical resolution of touchscreen > > > (maximum y coordinate reported + 1) > > > > > > I hope this clarifies things and if you want to change anything let > > > me know. > > > > Right, except that my concern is that people do not read documentation, > > and therefore will not realize that touchscreen-size-x is not the "true" > > what I called it, or what you call usable range, but rather maximum > > coordinate (-1). IOW I am concerned that if we have a device with > > 640x480 screen for example, and touch controller reporting coordinates > > with offset of 20, someone will specify: > > > > touchscreen-min-x = 20 > > touchscreen-size-x = 640 (because that's their screen size) > > > > and will not notice for some reason and later quirk it in their > > software. > > Ah I see. > > > So I was asking if we should accommodate this, and actually set up max > > on axis as "touchscreen-min-x + touchscreen-size-x - 1". It will still > > be compatible with current bindings (having effectively min of 0), but > > to me better reflects the name of the parameter - size of the screen. > > > > Please let me know if this makes any sense to you. > > I understand what you want now and why you want it. > > But I'm not sure I agree with you. Some pre-cursor to this patch series > actually had something like touchscreen-offset-x (or some-such I don't > remember) which actually subtracted the specified value from the coordinates > reported to userspace (clamping to 0). > > In that setup I think setting: > > touchscreen-size-x = (maximum x coordinate reported + 1) - > (minimum x coordinate reported. > > Makes sense, but since now we are not doing that and just copying the > values over to input_absinfo.minimum/maximum I think a 1:1 mapping > (with the - 1 adjustment for size) makes more sense. > > The way I'm currently using this is with touchscreens where we cannot > read this info from the hardware, so I repeatedly move my finger over > each edge noting down the min / max value for e.g. the left/right > edge and then directly putting these into the properties. > > IMHO not having to do some math here to calculate the right value > for touchscreen-size-x shows that treating touchscreen-size-x as > (touchscreen-max-x + 1) is the right thing to do. > > I'm actually worried that if we follow your suggestion people will > indeed not read the docs and thus not do the math. I think they will > just copy over the min / max readings and we and up with an > input_absinfo.maximum value which is input_absinfo.minimum > units too big. I see. OK, let's keep it your way. Applied. Thanks. -- Dmitry
