Re: [9front] [patch] aux/wacom: prevent "no concurrent reads please" error when moving the pen too fast and support screen tilt

[cinap_lenrek@felloff.net]

the way todo this is using srvrelease()/srvacquire():

          Srvrelease temporarily releases the calling process from the
          server loop and if neccesary spawns a new process to handle
          9p requests. When released, the process can do blocking work
          that would otherwise halt processing of 9p requests.
          Srvacquire rejoins the calling process with the server loop
          after a srvrelease.

also, what i dont like is polling /dev/vgactl. the tiling
feature is currently pc specific as other ports do not have
a vga device.

it is not obvious to me why tiling the screen would need
also rotating the tablet axis. for example, tiling might
just be used to compensate on how the display panel got
mounted in a laptop. the panel should just be scaled
to the *logical* screen dimensions. the kernels devmouse
driver already allows this by having a scaled versions
of the mousein command ("a" command, see scmousetrack()
in /sys/src/9/port/devmouse.c).

in any case, if we need axis change for tablets, we should
have this as a separate setting... independent of devvga.

--
cinap