Arbitrarily matching a screen to a touchscreen if event range/resolution match fails

Sometimes a touchmonitor's touch event reporting range has no correlation with
the touchmonitor's resolution, e.g. Acer T232HL has a native resolution of
1920x1080 but reports touch event range at 32767x32767. In this case using
the touch event range to match the touchmonitor's resolution will fail.

This CL adds that if there are unmatched touchscreens after using event range/resolution
information, match them to arbitrary unmatched screens.

This mostly helps the case of Pixel with external touchmonitor. Since Pixel's
internal screen is always matched to its internal touchscreen, if we ever have
an external touchsrceen that can't be matched, it will be forced to match to
external screen.

BUG=266106
TEST=Extended mode on Pixel with Acer T232HL works.

Review URL: https://chromiumcodereview.appspot.com/23256002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@217953 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 29 insertions, 5 deletions

diff --git a/chromeos/display/real_output_configurator_delegate.cc b/chromeos/display/real_output_configurator_delegate.cc
index 47fbd58..5b2d3c7 100644
--- a/chromeos/display/real_output_configurator_delegate.cc
+++ b/chromeos/display/real_output_configurator_delegate.cc
@@ -12,6 +12,7 @@
 #include <X11/extensions/Xrandr.h>
 
 #include <cmath>
+#include <set>
 
 #include "base/logging.h"
 #include "base/message_loop/message_pump_aurax11.h"
@@ -510,6 +511,7 @@ void RealOutputConfiguratorDelegate::GetTouchscreens(
   if (valuator_x == None || valuator_y == None)
     return;
 
+  std::set<int> no_match_touchscreen;
   XIDeviceInfo* info = XIQueryDevice(display_, XIAllDevices, &ndevices);
   for (int i = 0; i < ndevices; i++) {
     if (!info[i].enabled || info[i].use != XIFloatingSlave)
@@ -579,11 +581,33 @@ void RealOutputConfiguratorDelegate::GetTouchscreens(
         }
       }
 
-      VLOG_IF(2, k == outputs->size())
-          << "No matching output - ignoring touchscreen"
-          << " id " << info[i].deviceid
-          << " width " << width
-          << " height " << height;
+      if (k == outputs->size()) {
+        no_match_touchscreen.insert(info[i].deviceid);
+        VLOG(2) << "No matching output for touchscreen"
+                << " id " << info[i].deviceid
+                << " width " << width
+                << " height " << height;
+      }
+
+    }
+  }
+
+  // Sometimes we can't find a matching screen for the touchscreen, e.g.
+  // due to the touchscreen's reporting range having no correlation with the
+  // screen's resolution. In this case, we arbitrarily assign unmatched
+  // touchscreens to unmatched screens.
+  for (std::set<int>::iterator it = no_match_touchscreen.begin();
+       it != no_match_touchscreen.end();
+       it++) {
+    for (size_t i = 0; i < outputs->size(); i++) {
+      if ((*outputs)[i].is_internal == false &&
+          (*outputs)[i].native_mode != None &&
+          (*outputs)[i].touch_device_id == None ) {
+        (*outputs)[i].touch_device_id = *it;
+        VLOG(2) << "Arbitrarily matching touchscreen "
+                << (*outputs)[i].touch_device_id << " to output #" << i;
+        break;
+      }
     }
   }