dix: add dtrace probes to input API

For driver debugging, it is helpful to know whether the driver has actually
submitted an event to the server. dtrace hooks can help here.

Note that GetPointerEvents and friends may also be triggered by the server
for other emulated devices, some care must be taken when analysing the
results.

Additional difficulty: proximity events have a run-time assigned type, so
this may make automatic detection a tad harder. If in doubt, go for any
event > 64 since the only two that can have that value are ProximityIn and
ProximityOut.

An example systemtap script is below:

  # Compile+run with
  #       stap -g xorg.stp /usr/bin/Xorg
  #

  function print_valuators:string(nvaluators:long, mask_in:long, valuators_in:long) %{
          int i;
          unsigned char *mask = (unsigned char*)THIS->mask_in;
          double *valuators = (double*)THIS->valuators_in;
          char str[128] = {0};
          char *s = str;

  #define BitIsSet(ptr, bit) (((unsigned char*)(ptr))[(bit)>>3] & (1 << ((bit) & 7)))

          s += sprintf(s, "nval: %d ::", (int)THIS->nvaluators);
          for (i = 0; i < THIS->nvaluators; i++)
          {
                  s += sprintf(s, "	%d: ", i);
                  if (BitIsSet(mask, i))
                      s += sprintf(s, "%d", (int)valuators[i]);
          }

          sprintf(THIS->__retvalue, "%s", str);
  %}

  probe process(@1).mark("input__event")
  {
      deviceid = $arg1
      type = $arg2
      detail = $arg3
      flags = $arg4
      nvaluators = $arg5

      str = print_valuators(nvaluators, $arg6, $arg7)
      printf("Event: device %d type %d detail %d flags %#x %s\n",
              deviceid, type, detail, flags, str);
  }

Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>
Acked-by: Jeremy Huddleston <jeremyhu@apple.com>

1 files changed, 42 insertions, 0 deletions

diff --git a/dix/getevents.c b/dix/getevents.c
index 2f6f06ced..6354e99ef 100644
--- a/dix/getevents.c
+++ b/dix/getevents.c
@@ -68,6 +68,12 @@
 #include "extnsionst.h"
 #include "listdev.h"            /* for sizing up DeviceClassesChangedEvent */
 
+#if XSERVER_DTRACE
+#include <sys/types.h>
+typedef const char *string;
+#include <Xserver-dtrace.h>
+#endif
+
 /* Number of motion history events to store. */
 #define MOTION_HISTORY_SIZE 256
 
@@ -1025,6 +1031,15 @@ GetKeyboardEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
     RawDeviceEvent *raw;
     ValuatorMask mask;
 
+#if XSERVER_DTRACE
+    if (XSERVER_INPUT_EVENT_ENABLED()) {
+        XSERVER_INPUT_EVENT(pDev->id, type, key_code, 0,
+                            mask_in ? mask_in->last_bit + 1 : 0,
+                            mask_in ? mask_in->mask : NULL,
+                            mask_in ? mask_in->valuators : NULL);
+    }
+#endif
+
     /* refuse events from disabled devices */
     if (!pDev->enabled)
         return 0;
@@ -1501,6 +1516,15 @@ GetPointerEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
     int i;
     int realtype = type;
 
+#if XSERVER_DTRACE
+    if (XSERVER_INPUT_EVENT_ENABLED()) {
+        XSERVER_INPUT_EVENT(pDev->id, type, buttons, flags,
+                            mask_in ? mask_in->last_bit + 1 : 0,
+                            mask_in ? mask_in->mask : NULL,
+                            mask_in ? mask_in->valuators : NULL);
+    }
+#endif
+
     /* refuse events from disabled devices */
     if (!pDev->enabled)
         return 0;
@@ -1626,6 +1650,15 @@ GetProximityEvents(InternalEvent *events, DeviceIntPtr pDev, int type,
     DeviceEvent *event;
     ValuatorMask mask;
 
+#if XSERVER_DTRACE
+    if (XSERVER_INPUT_EVENT_ENABLED()) {
+        XSERVER_INPUT_EVENT(pDev->id, type, 0, 0,
+                            mask_in ? mask_in->last_bit + 1 : 0,
+                            mask_in ? mask_in->mask : NULL,
+                            mask_in ? mask_in->valuators : NULL);
+    }
+#endif
+
     /* refuse events from disabled devices */
     if (!pDev->enabled)
         return 0;
@@ -1750,6 +1783,15 @@ GetTouchEvents(InternalEvent *events, DeviceIntPtr dev, uint32_t ddx_touchid,
     Bool emulate_pointer = FALSE;
     int client_id = 0;
 
+#if XSERVER_DTRACE
+    if (XSERVER_INPUT_EVENT_ENABLED()) {
+        XSERVER_INPUT_EVENT(dev->id, type, ddx_touchid, flags,
+                            mask_in ? mask_in->last_bit + 1 : 0,
+                            mask_in ? mask_in->mask : NULL,
+                            mask_in ? mask_in->valuators : NULL);
+    }
+#endif
+
     if (!dev->enabled || !t || !v)
         return 0;