Merge lp:~hui.wang/unity-settings-daemon/unity-settings-daemon-1404-fix-touchscreen-reconnect into lp:unity-settings-daemon/14.04

[Hui Wang]

We have an OEM bug, it has something to do with the u-s-d
touchscreen mapping, Please take a look. thanks.

https://bugs.launchpad.net/sutton/hwe-sutton/+bug/1530063

This is my investigation:

When we change the display resolution, the LG touchscreen will be
disconnected from usb host bus temporarily.

And at that time, the unity-settings-daemon will call on_randr_event
(GnomeRRScreen *screen, gpointer data)-->do_touchscreen_mapping
(GsdXrandrManager *manager)-->get_mappable_output_info
(GsdXrandrManager *manager, GnomeRRScreen *screen, GnomeRRConfig
*config)-->input_info_find_size_match (GsdXrandrManager *manager,
GnomeRRScreen *rr_screen)-->xdevice_get_dimensions (int deviceid,
guint *width, guint *height)-->XIQueryDevice (GDK_DISPLAY_XDISPLAY
(display), deviceid, &n_info) CRASHED IN THIS FUNCTION

It looks like the usb touchscreen is disconnected temporarily, but
the unity-settings-daemon does not know it, it finally call
XIQueryDevice() to query this input device, then it crash inside
this function.

This is the kernel log when changing display resolution:
  [ 62.941417] usb 1-10: USB disconnect, device number 7
[ 63.777166] do_trap: 154 callbacks suppressed
[ 63.777171] traps: unity-settings-[2178] trap int3
ip:7f8a69913c13 sp:7ffd1829bb50 error:0
[ 63.935059] usb 1-10: new full-speed USB device number 8 using xhci_hcd
[ 64.119528] usb 1-10: not running at top speed; connect to a high
speed hub
[ 64.120303] usb 1-10: New USB device found, idVendor=1fd2, idProduct=5003
[ 64.120305] usb 1-10: New USB device strings: Mfr=1, Product=2,
SerialNumber=0
[ 64.120307] usb 1-10: Product: LGD AIT Touch Controller
[ 64.120308] usb 1-10: Manufacturer: Melfas
[ 64.123083] input: Melfas LGD AIT Touch Controller as /devices/pci0000:00/0000:00:14.0/usb1/1-10/1-10:1.0/0003:1FD2:5003.0004/input/input19
[ 64.175930] hid-multitouch 0003:1FD2:5003.0004:
input,hiddev0,hidraw1: USB HID v1.11 Mouse [Melfas LGD AIT Touch
Controller] on usb-0000:00:14.0-10/input0
[ 64.176589] hid-generic 0003:1FD2:5003.0005: hiddev0,hidraw2: USB
HID v1.11 Device [Melfas LGD AIT Touch Controller] on
usb-0000:00:14.0-10/input1

[Alberto Milone (albertomilone)]

The code looks good to me. It seems like a reasonable workaround. Thanks.

review: Approve

[Sebastien Bacher (seb128)]

thanks for the work, settings as rejected as discussed on https://code.launchpad.net/~hui.wang/unity-settings-daemon/unity-settings-daemon-master-touchscreen-fix/+merge/293704 we are looking at a better solution

review: Disapprove

Unmerged revisions

4049. By Hui Wang on 2016-04-21

check and wait the touchscreen before calling do map

=== modified file 'plugins/xrandr/gsd-xrandr-manager.c'
--- plugins/xrandr/gsd-xrandr-manager.c	2015-09-22 08:29:34 +0000
+++ plugins/xrandr/gsd-xrandr-manager.c	2016-05-04 02:04:57 +0000
@@ -1784,6 +1784,56 @@
                 log_msg ("Applied stored configuration\n");
 }
 
+/* At least on a Lenovo laptop with the LG LCD panel and the LG touchscreen,
+   when we change the display resolution, the LG touchscreen will be temporarily
+   disconnected from USB host bus for about 0.2 seconds, then will be
+   reconnected to the USB host bus. If we let the system call
+   do_touchscreen_mapping() before the reconnectting, the u-s-d will crash.
+   
+   So we let system check and wait 2 seconds at most for the touchscreen to be ready
+   again, if the touchscreen can't be ready after 2 seconds, we will think the
+   touchscreen is disconnected.
+*/
+#define RETRY_TIMES 2
+static gboolean
+is_touchscreen_still_available (GsdXrandrManager *manager)
+{
+        GsdXrandrManagerPrivate *priv = manager->priv;
+        XDeviceInfo *device_info;
+        int n_devices;
+        int i;
+        gboolean ret = FALSE;
+        int rtime = 0;
+retry:
+        device_info = XListInputDevices (GDK_DISPLAY_XDISPLAY (gdk_display_get_default ()),
+                                         &n_devices);
+        if (device_info == NULL)
+                return ret;
+
+        for (i = 0; i < n_devices; i++) {
+                if (device_info_is_touchscreen (&device_info[i])) {
+                         if (!strcmp(priv->main_touchscreen_name, g_strdup (device_info[i].name))) {
+                                ret = TRUE;
+                                break;
+                        }
+                }
+        }
+
+        XFreeDeviceList (device_info);
+
+        if (ret)
+                return ret;
+
+        if (rtime++ < RETRY_TIMES) {
+                sleep(1); /* sleep 1 second */
+                goto retry;
+        } else {
+                priv->main_touchscreen_id = -1;
+                priv->main_touchscreen_name = NULL;
+                return ret;
+        }
+}
+
 static void
 on_randr_event (GnomeRRScreen *screen, gpointer data)
 {
@@ -1837,7 +1887,7 @@
                 use_stored_configuration_or_auto_configure_outputs (manager, config_timestamp);
         }
 
-        if (priv->main_touchscreen_id != -1) {
+        if (priv->main_touchscreen_id != -1 && is_touchscreen_still_available(manager)) {
                 /* Set mapping of input devices onto displays */
                 log_msg ("\nSetting touchscreen mapping on RandR event\n");
                 do_touchscreen_mapping (manager);