Re: [Qemu-devel] [PATCH] [RFC] usb-wacom

[François Revol]

> Can you please send the patch to the mailing list attached as a
> text/plain attachment or inlined.  Then we can review and possibly
> commit it.

Sorry, not used to this ml.
Here it is.
Btw, you top-posted ;)

François.

> François Revol wrote:
> > Hi there.
> > We use QEMU a lot to debug Haiku, http://haiku-os.org/
> > I also wrote a little php script that use it to demo images online,
> > serving a VNC java applet to connect to it with VNC.
> > http://dev.haiku-os.org/browser/haiku/trunk/3rdparty/mmu_man/onlinedemo/haiku.php
> > > > It's a bit like what live.OSZoo does, but simpler.
> >
> > To accomodate the VNC setup, I tried to use the usb tablet
> > emulation.
> > It turns out Haiku has a driver for Wacom tablets:
> >
> > http://dev.haiku-os.org/browser/haiku/trunk/src/add-ons/kernel/drivers/input/wacom
> > > > http://dev.haiku-os.org/browser/haiku/trunk/src/add-ons/input_server/devices/wacom
> > > >
> > However, it didn't really work very well with qemu's usb-wacom
> > code.
> >
> > First, mouse stayed in the top-left corner... Seems coords were set
> > to
> > 0,0 when no button is pressed, which is wrong, most tablets
> > actually
> > sense the stylus even when it's not yet touching the surface.
> >
> > Also, coords were wrong.
> > Our driver takes the pos from the hardware, and scales them from
> > model-
> > dependant hardcoded max values:
> > http://dev.haiku-os.org/browser/haiku/trunk/src/add-ons/input_server/devices/wacom/TabletDevice.cpp#L115
> > > > down to [0.0f, 1.0f], which represents the whole screen.
> > Since QEMU reports absolute mouse position scaled from screen size
> > to
> > INT16_MAX this didn't really work.
> > Now, I'm not sure those max values are correct for all Penpartner
> > devices, or if they were calibrated on a specific item.
> > Best would be to actually read them from the HID descriptor, but
> > QEMU
> > doesn't provide one, and I read some penpartner tablets actually
> > have
> > wrong descriptors anyway.
> >
> > Finaly, I fixed button handling according to our driver, not sure
> > all
> > drivers handle them the same. pressure indicates left button, and a
> > flag tells about right one. I mapped middle button to the eraser to
> > at
> > least be useful in tablet-aware software though I'm not sure it's
> > the
> > best way.
> >
> > And... oh well seems we don't need to tell we have a contact, the
> > driver assumes it always for penpartner so it seems correct.
> >
> > I left debug macro I used just in case.
> >
> > http://revolf.free.fr/beos/patches/qemu-usb-wacom-for-haiku.diff.txt
> > > >
> > Now at least it works perfectly with our driver, appart from high
> > cpu
> > usage but that's surely be fixed by polling less often.
> >
> > Comments ?

Index: hw/usb-wacom.c
===================================================================
--- hw/usb-wacom.c      (révision 5002)
+++ hw/usb-wacom.c      (copie de travail)
@@ -29,6 +29,16 @@
 #include "console.h"
 #include "usb.h"
 
+/* debug usb-wacom */
+//#define DEBUG_USB_WACOM
+
+#ifdef DEBUG_USB_WACOM
+#define DPRINTF(fmt, args...) \
+do { printf("usb-wacom: " fmt , ##args); } while (0)
+#else
+#define DPRINTF(fmt, args...)
+#endif
+
 /* Interface requests */
 #define WACOM_GET_REPORT       0x2101
 #define WACOM_SET_REPORT       0x2109
@@ -132,8 +142,8 @@
 {
     USBWacomState *s = opaque;
 
-    s->x = x;
-    s->y = y;
+    s->x = (x * 5040 / 0x7FFF);
+    s->y = (y * 3780 / 0x7FFF);
     s->dz += dz;
     s->buttons_state = buttons_state;
 }
@@ -199,26 +209,22 @@
     if (s->buttons_state & MOUSE_EVENT_LBUTTON)
         b |= 0x01;
     if (s->buttons_state & MOUSE_EVENT_RBUTTON)
-        b |= 0x02;
+        b |= 0x40;
     if (s->buttons_state & MOUSE_EVENT_MBUTTON)
-        b |= 0x04;
+        b |= 0x20; /* eraser */
 
     if (len < 7)
         return 0;
 
     buf[0] = s->mode;
-    buf[5] = 0x00;
-    if (b) {
-        buf[1] = s->x & 0xff;
-        buf[2] = s->x >> 8;
-        buf[3] = s->y & 0xff;
-        buf[4] = s->y >> 8;
+    buf[5] = 0x00 | (b & 0xf0);
+    buf[1] = s->x & 0xff;
+    buf[2] = s->x >> 8;
+    buf[3] = s->y & 0xff;
+    buf[4] = s->y >> 8;
+    if (b & 0x3f) {
         buf[6] = 0;
     } else {
-        buf[1] = 0;
-        buf[2] = 0;
-        buf[3] = 0;
-        buf[4] = 0;
         buf[6] = (unsigned char) -127;
     }