PATCH: uep(4) support for (my) eGalax touchscreen

[Anthony Jenkins]

On 07/24/2017 03:28 PM, Anthony Jenkins via freebsd-usb wrote:
> I'm trying to add support for uep(4) to detect and properly emit touch
> events to x11-drivers/xf86-input-egalax. What I have works, but has some
> issues, particularly:
>
>  - close(2)ing the device node causes a USB_ST_ERROR in the
> uep_intr_callback(); it's probably from my attempt to port an
> initialization control message from Linux
>  - I massage the touch events from my device into the legacy uep(4)
> event structure since my multitouch-supporting touchscreen has 12-bits
> of resolution per axis, but legacy uep(4) only had 11
>  - For some reason my Y-axis is inverted; I had to subtract its
> coordinate from the max Y value.  I'll probably add an ioctl(2) to set
> axis inversion behavior dynamically rather than hardcode it.
>  - I capture all the multitouch info from the USB packets, but I don't
> know (yet) if xf86-input-egalax can do anything with it
>  - x11-drivers/xf86-input-egalax's default min/max ranges are "silly"
> (500/1500), but I didn't add the trivial patch to it.  I'd like to add
> an ioctl(2) that lets xf86-input-egalax query uep(4) for axis ranges,
> but as I've written my patch, uep(4) doesn't know its ranges until it
> gets a touch packet.
>  - I started adding support for evdev(4) reporting (added header files
> and device struct members), but it's nowhere near finished.
>  - I have no idea how common this eGalax protocol is or how to determine
> what protocol to use from the driver.  Right now I assume a byte 0 of
> 0x06 means "multitouch event".
>  - My x11-servers/xorg-server is patched to associate /dev/uep0 with the
> xf86-input-egalax driver; I guess I'll have to make that available too. 
> My config/devd.c is substantially different from stock.

The main problem with uep(4) was either xorg-server or xf86-input-egalax
started doing asynchronous I/O on the device node using fcntl(F_SETOWN);
the original uep(4) expected userland to open(2)/read(2) the device
node.  I had to add the FIOSETOWN support, but I don't know if there's a
way to remove a process as owner (call fcntl(F_SETOWN, NULL)?).  If so,
I'll need to handle that case.

I can stick this up in the FreeBSD code review site if desired.

Anthony

> Logging is sort of noisy at the moment when touching the screen, but it
> "Just Works (TM)" with my touchscreen, my slightly-patched
> xf86-input-egalax driver and KDE4.
>
> uep(4) patch:
> https://github.com/ScoobiFreeBSD/freebsd/commit/62c11d484d5fb61749240b439612f852c5148222
> x11-servers/xorg-server patch:
> https://github.com/ScoobiFreeBSD/freebsd-ports/commit/9465237f83ab8fb27249abfe803f94b6b8c3b945
>
> Suggestions/comments welcome.  Currently looking for help with the
> USB_ST_ERROR issue, although I think I may know what's wrong (this is my
> 1st attempt at USB stack programming).
>
> Anthony Jenkins
>
> _______________________________________________
> freebsd-usb at freebsd.org mailing list
> https://lists.freebsd.org/mailman/listinfo/freebsd-usb
> To unsubscribe, send any mail to "freebsd-usb-unsubscribe at freebsd.org"

-- 
Anthony Jenkins