Hi Pali, > Am 20.02.2017 um 23:04 schrieb Pali Rohár <pali.rohar@xxxxxxxxx>: > > On Monday 20 February 2017 22:27:39 H. Nikolaus Schaller wrote: >>> Am 20.02.2017 um 22:08 schrieb Pali Rohár <pali.rohar@xxxxxxxxx>: >>> >>> On Monday 20 February 2017 20:42:15 Pali Rohár wrote: >>>> While I'm watching this discussion... in my opinion kernel should >>>> just invert input axes (when needed) >> >> It is questionable why it should do that at all then. >> >> User-Space can also easily do it. Either the driver should provide >> raw data only or if it does pre-processing (scaling by +/-1), why >> exclude pre-scaling by other factors? > > Via resolution property which is in that EVIOCSABS ioctl() you specify > value which represent unit per mm. So you cannot do full rescaling like > via affine transformation. Specially you cannot swap axes or invert it. > > As such thing is not supported by current kernel <--> userspace API it > needs to be done in kernel. Then, this what you asked for to be missing in the ABI and should be added to clean upt the kernel drivers. > > Moreover I see that this is already handled by kernel's of_touchscreen.c > code via DT properties: touchscreen-inverted-* touchscreen-swapped-x-y Should be removed IMHO because user-space can do it equally well. By setting the affine transform to negative values or use something like ((0 -1) (1 0)) Or it should be processed as a generic value by the input core and should not need to be implemented in every driver again and again. If input core would handle these properties in a generic way, this patch is no longer necessary (wrt flipping and rotation). So please fix the input core so that it makes life of device driver developers easier. > > And... I'm not sure but I think that linux exports absolute input > devices with coordinates where point (0,0) is mapped as left upper > corner. > >>>> and should not do any other >>>> normalization or integer/floating-point >>>> re-calibration/re-calculation. If it correctly exports minimum >>>> value, maximum value and resolution then userspace can correctly >>>> re-scale input events to units which userspace needs (e.g. mapping >>>> into LCD screen pixels or whatever is needed). BR and thanks, Nikolaus
Attachment:
signature.asc
Description: Message signed with OpenPGP using GPGMail
