On Thu, Apr 27, 2023 at 12:23:14PM -0500, Jeff LaBundy wrote: > Hi Javier, > > On Thu, Apr 27, 2023 at 05:59:42PM +0200, Javier Carrasco wrote: > > Hi, > > > > On 25.04.23 18:02, Jeff LaBundy wrote: > > > Hi Thomas, > > > > > > On Tue, Apr 25, 2023 at 05:29:39PM +0200, Thomas Weißschuh wrote: > > >> Hi Javier, > > >> > > >> On 2023-04-25 13:50:45+0200, Javier Carrasco wrote: > > >>> Some touchscreens are shipped with a physical layer on top of them where > > >>> a number of buttons and a resized touchscreen surface might be available. > > >>> > > >>> In order to generate proper key events by overlay buttons and adjust the > > >>> touch events to a clipped surface, these patches offer a documented, > > >>> device-tree-based solution by means of helper functions. > > >>> An implementation for a specific touchscreen driver is also included. > > >>> > > >>> The functions in ts-virtobj provide a simple workflow to acquire > > >>> physical objects from the device tree, map them into the device driver > > >>> structures as virtual objects and generate events according to > > >>> the object descriptions. > > >>> > > >>> This solution has been tested with a JT240MHQS-E3 display, which uses > > >>> the st1624 as a touchscreen and provides two overly buttons and a frame > > >>> that clips its effective surface. > > >> > > >> There are quite a few of notebooks from Asus that feature a printed > > >> numpad on their touchpad [0]. The mapping from the touch events to the > > >> numpad events needs to happen in software. > > > > > > That example seems a kind of fringe use-case in my opinion; I think the > > > gap filled by this RFC is the case where a touchscreen has a printed > > > overlay with a key that represents a fixed function. > > > > Exactly, this RFC addresses exactly such printed overlays. > > > > > > One problem I do see here is something like libinput or multitouch taking > > > hold of the input device, and swallowing the key presses because it sees > > > the device as a touchscreen and is not interested in these keys. > > > > Unfortunately I do not know libinput or multitouch and I might be > > getting you wrong, but I guess the same would apply to any event > > consumer that takes touchscreens as touch event producers and nothing else. > > > > Should they not check the supported events from the device instead of > > making such assumptions? This RFC adds key events defined in the device > > tree and they are therefore available and published as device > > capabilities. That is for example what evtest does to report the > > supported events and they are then notified accordingly. Is that not the > > right way to do it? > > evtest is just that, a test tool. It's handy for ensuring the device emits > the appropriate input events in response to hardware inputs, but it is not > necessarily representative of how the input device may be used in practice. ftr, I strongly recommend "libinput record" over evtest since it can be replayed. And for libinput testing "libinput debug-events" to see what comes out of libinput. > I would encourage you to test this solution with a simple use-case such as > Raspbian, and the virtual keys mapped to easily recognizable functions like > volume up/down. > > Here, you will find that libinput will grab the device and declare it to be > a touchscreen based on the input events it advertises. However, you will not > see volume up/down keys are handled. that would be a bug in libinput. libinput doesn't classify devices. It uses *internal* backends but the backend for keyboard and touchscreen devices is the same. So as long as your device advertises the various EV_KEY and EV_ABS bit correctly, things should just work. If that's not the case for a device please file a bug. It's still "better" to split it up into different event nodes because a lot of userspace may not be able to handle touchscreen+keyboard devices but at least at the libinput level this shouldn't be a problem. And the xf86-input-libinput driver splits up such devices at the X level, so even where a device is touchscreen + keyboard you would end up with two X devices with separate capabilities so they fit into the X "everything is either a pointer or a keyboard" worldview. Cheers, Peter
