[PATCH xserver 3/3] ddx: add new call to purge input devices that weren't added

[Peter Hutterer]

Special case for the systemd-logind case in xfree86: when we're vt-switched
away and a device is plugged in, we get a paused fd from logind. Since we
can't probe the device or do anything with it, we store that device in the
xfree86 and handle it later when we vt-switch back. The device is not added to
inputInfo.devices until that time.

When the device is removed while still vt-switched away, the the config system
never notifies the DDX. It only runs through inputInfo.devices and our device
was never added to that.

When a device is plugged in, removed, and plugged in again while vt-switched
away, we have two entries in the xfree86-specific list that refer to the same
device node, both pending for addition later. On VT switch back, the first one
(the already removed one) will be added successfully, the second one (the
still plugged-in one) fails. Since the fd is correct, the device works until
it is removed again. The removed devices' config_info (i.e. the syspath)
doesn't match the actual device we addded tough (the input number increases
with each plug), it doesn't get removed, the fd remains open and we lose track
of the fd count. Plugging the device in again leads to a dead device.

Fix this by adding a call to notify the DDX to purge any remainders of devices
with the given config_info, that's the only identifiable bit we have at this
point.

https://bugs.freedesktop.org/show_bug.cgi?id=97928

Signed-off-by: Peter Hutterer <peter.hutterer at who-t.net>
---
 Xi/stubs.c                     | 14 ++++++++++++++
 config/config.c                |  2 ++
 hw/dmx/dmxinput.c              |  5 +++++
 hw/kdrive/src/kinput.c         |  5 +++++
 hw/xfree86/common/xf86Xinput.c | 19 +++++++++++++++++++
 hw/xquartz/darwinXinput.c      | 15 +++++++++++++++
 include/input.h                |  1 +
 7 files changed, 61 insertions(+)

diff --git a/Xi/stubs.c b/Xi/stubs.c
index 39bee7c..27848a2 100644
--- a/Xi/stubs.c
+++ b/Xi/stubs.c
@@ -143,3 +143,17 @@ DeleteInputDeviceRequest(DeviceIntPtr dev)
 {
     RemoveDevice(dev, TRUE);
 }
+
+/****************************************************************************
+ *
+ * Caller: configRemoveDevice (and others)
+ *
+ * Remove any traces of the input device specified in config_info.
+ * This is only necessary if the ddx keeps information around beyond
+ * the NewInputDeviceRequest/DeleteInputDeviceRequest
+ *
+ */
+void
+RemoveInputDeviceTraces(const char *config_info)
+{
+}
diff --git a/config/config.c b/config/config.c
index 1fb368c..fb60295 100644
--- a/config/config.c
+++ b/config/config.c
@@ -107,6 +107,8 @@ remove_devices(const char *backend, const char *config_info)
         if (dev->config_info && strcmp(dev->config_info, config_info) == 0)
             remove_device(backend, dev);
     }
+
+    RemoveInputDeviceTraces(config_info);
 }
 
 BOOL
diff --git a/hw/dmx/dmxinput.c b/hw/dmx/dmxinput.c
index 4ccb439..d201034 100644
--- a/hw/dmx/dmxinput.c
+++ b/hw/dmx/dmxinput.c
@@ -123,3 +123,8 @@ void
 DeleteInputDeviceRequest(DeviceIntPtr pDev)
 {
 }
+
+void
+RemoveInputDeviceTraces(const char *config_info)
+{
+}
diff --git a/hw/kdrive/src/kinput.c b/hw/kdrive/src/kinput.c
index 2c39624..8b08747 100644
--- a/hw/kdrive/src/kinput.c
+++ b/hw/kdrive/src/kinput.c
@@ -2302,3 +2302,8 @@ DeleteInputDeviceRequest(DeviceIntPtr pDev)
 {
     RemoveDevice(pDev, TRUE);
 }
+
+void
+RemoveInputDeviceTraces(const char *config_info)
+{
+}
diff --git a/hw/xfree86/common/xf86Xinput.c b/hw/xfree86/common/xf86Xinput.c
index 0095272..d673711 100644
--- a/hw/xfree86/common/xf86Xinput.c
+++ b/hw/xfree86/common/xf86Xinput.c
@@ -1119,6 +1119,25 @@ DeleteInputDeviceRequest(DeviceIntPtr pDev)
     input_unlock();
 }
 
+void
+RemoveInputDeviceTraces(const char *config_info)
+{
+    PausedInputDevicePtr d, tmp;
+
+    if (new_input_devices_list.next == NULL &&
+        new_input_devices_list.prev == NULL)
+        xorg_list_init(&new_input_devices_list);
+
+    xorg_list_for_each_entry_safe(d, tmp, &new_input_devices_list, node) {
+        const char *ci = xf86findOptionValue(d->pInfo->options, "config_info");
+        if (!ci || strcmp(ci, config_info) != 0)
+            continue;
+
+        xorg_list_del(&d->node);
+        free(d);
+    }
+}
+
 /*
  * convenient functions to post events
  */
diff --git a/hw/xquartz/darwinXinput.c b/hw/xquartz/darwinXinput.c
index 3efaa2c..fea7e92 100644
--- a/hw/xquartz/darwinXinput.c
+++ b/hw/xquartz/darwinXinput.c
@@ -147,3 +147,18 @@ DeleteInputDeviceRequest(DeviceIntPtr dev)
 {
     DEBUG_LOG("DeleteInputDeviceRequest(%p)\n", dev);
 }
+
+/****************************************************************************
+ *
+ * Caller: configRemoveDevice (and others)
+ *
+ * Remove any traces of the input device specified in config_info.
+ * This is only necessary if the ddx keeps information around beyond
+ * the NewInputDeviceRequest/DeleteInputDeviceRequest
+ *
+ */
+void
+RemoveInputDeviceTraces(const char *config_info)
+{
+    DEBUG_LOG("RemoveInputDeviceTraces(%s)\n", config_info);
+}
diff --git a/include/input.h b/include/input.h
index c7b1e91..bb58b22 100644
--- a/include/input.h
+++ b/include/input.h
@@ -635,6 +635,7 @@ extern _X_EXPORT int NewInputDeviceRequest(InputOption *options,
                                            InputAttributes * attrs,
                                            DeviceIntPtr *dev);
 extern _X_EXPORT void DeleteInputDeviceRequest(DeviceIntPtr dev);
+extern _X_EXPORT void RemoveInputDeviceTraces(const char *config_info);
 
 extern _X_EXPORT void DDXRingBell(int volume, int pitch, int duration);
 
-- 
2.9.3