Attempt to re-open devices on read errors.

Coming back from resume may leave us with a file descriptor that can be opened
but fails on the first read (ENODEV).
In this case, try to open the device until it becomes available or until the
predefined count expires. To be safe, we cache the information from the device
and compare against it when we re-open. This way we ensure that if the
topology changes under us, we don't open a completely different device. If a
device has changed, we disable it.

Adds option "ReopenAttempts" <int>

Conflicts:

	man/evdev.man
	src/evdev.c
	src/evdev.h

3 files changed, 268 insertions, 21 deletions

diff --git a/man/evdev.man b/man/evdev.man
index f438f78..530f979 100644
--- a/man/evdev.man
+++ b/man/evdev.man
@@ -67,6 +67,11 @@ button event is registered.
 Sets the timeout (in milliseconds) that the driver waits before deciding
 if two buttons where pressed "simultaneously" when 3 button emulation is
 enabled.  Default: 50.
+.TP 7
+.BI "Option \*qReopenAttempts\*q \*q" integer \*q
+Number of reopen attempts after a read error occurs on the device (e.g. after
+waking up from suspend). In between each attempt is a 100ms wait. Default: 10.
+
 .SH AUTHORS
 Kristian Høgsberg.
 .SH "SEE ALSO"
diff --git a/src/evdev.c b/src/evdev.c
index a857db3..c0fe244 100644
--- a/src/evdev.c
+++ b/src/evdev.c
@@ -73,6 +73,7 @@
 #define EVDEV_RELATIVE_EVENTS	(1 << 2)
 #define EVDEV_ABSOLUTE_EVENTS	(1 << 3)
 #define EVDEV_TOUCHPAD		(1 << 4)
+#define EVDEV_INITIALIZED	(1 << 5) /* WheelInit etc. called already? */
 
 #define MIN_KEYCODE 8
 #define GLYPHS_PER_KEY 2
@@ -96,6 +97,9 @@ static const char *evdevDefaults[] = {
     NULL
 };
 
+static int EvdevOn(DeviceIntPtr);
+static int EvdevCacheCompare(InputInfoPtr pInfo, Bool compare);
+
 static void
 SetXkbOption(InputInfoPtr pInfo, char *name, char **option)
 {
@@ -154,6 +158,55 @@ PostKbdEvent(InputInfoPtr pInfo, struct input_event *ev, int value)
     xf86PostKeyboardEvent(pInfo->dev, code, value);
 }
 
+/**
+ * Coming back from resume may leave us with a file descriptor that can be
+ * opened but fails on the first read (ENODEV).
+ * In this case, try to open the device until it becomes available or until
+ * the predefined count expires.
+ */
+static CARD32
+EvdevReopenTimer(OsTimerPtr timer, CARD32 time, pointer arg)
+{
+    InputInfoPtr pInfo = (InputInfoPtr)arg;
+    EvdevPtr pEvdev = pInfo->private;
+
+    do {
+        pInfo->fd = open(pEvdev->device, O_RDWR, 0);
+    } while (pInfo->fd < 0 && errno == EINTR);
+
+    if (pInfo->fd != -1)
+    {
+        pEvdev->reopen_left = 0;
+
+        if (EvdevCacheCompare(pInfo, TRUE) == Success)
+        {
+            xf86Msg(X_INFO, "%s: Device reopened after %d attempts.\n", pInfo->name,
+                    pEvdev->reopen_attempts - pEvdev->reopen_left);
+            EvdevOn(pInfo->dev);
+        } else
+        {
+            xf86Msg(X_ERROR, "%s: Device has changed - disabling.\n",
+                    pInfo->name);
+            DisableDevice(pInfo->dev);
+            close(pInfo->fd);
+            pInfo->fd = -1;
+        }
+        return 0;
+    }
+
+    pEvdev->reopen_left--;
+
+    if (!pEvdev->reopen_left)
+    {
+        xf86Msg(X_ERROR, "%s: Failed to reopen device after %d attempts.\n",
+                pInfo->name, pEvdev->reopen_attempts);
+        DisableDevice(pInfo->dev);
+        return 0;
+    }
+
+    return 100; /* come back in 100 ms */
+}
+
 static void
 EvdevReadInput(InputInfoPtr pInfo)
 {
@@ -173,6 +226,15 @@ EvdevReadInput(InputInfoPtr pInfo)
             /* The kernel promises that we always only read a complete
              * event, so len != sizeof ev is an error. */
             xf86Msg(X_ERROR, "%s: Read error: %s\n", pInfo->name, strerror(errno));
+
+            if (errno == ENODEV) /* May happen after resume */
+            {
+                xf86RemoveEnabledDevice(pInfo);
+                close(pInfo->fd);
+                pInfo->fd = -1;
+                pEvdev->reopen_left = pEvdev->reopen_attempts;
+                pEvdev->reopen_timer = TimerSet(NULL, 0, 100, EvdevReopenTimer, pInfo);
+            }
             break;
         }
 
@@ -316,8 +378,6 @@ EvdevReadInput(InputInfoPtr pInfo)
     }
 }
 
-#define LONG_BITS (sizeof(long) * 8)
-#define NBITS(x) (((x) + LONG_BITS - 1) / LONG_BITS)
 #define TestBit(bit, array) (array[(bit) / LONG_BITS]) & (1 << ((bit) % LONG_BITS))
 
 static void
@@ -836,6 +896,56 @@ EvdevInit(DeviceIntPtr device)
     return Success;
 }
 
+/**
+ * Init all extras (wheel emulation, etc.) and grab the device.
+ *
+ * Coming from a resume, the grab may fail with ENODEV. In this case, we set a
+ * timer to wake up and try to reopen the device later.
+ */
+static int
+EvdevOn(DeviceIntPtr device)
+{
+    InputInfoPtr pInfo;
+    EvdevPtr pEvdev;
+    int rc = 0;
+
+    pInfo = device->public.devicePrivate;
+    pEvdev = pInfo->private;
+
+    if (pInfo->fd != -1 && !pEvdev->kernel24 &&
+        (rc = ioctl(pInfo->fd, EVIOCGRAB, (void *)1)))
+    {
+        xf86Msg(X_WARNING, "%s: Grab failed (%s)\n", pInfo->name,
+                strerror(errno));
+
+        /* ENODEV - device has disappeared after resume */
+        if (rc && errno == ENODEV)
+        {
+            close(pInfo->fd);
+            pInfo->fd = -1;
+        }
+    }
+
+    if (pInfo->fd == -1)
+    {
+        pEvdev->reopen_left = pEvdev->reopen_attempts;
+        pEvdev->reopen_timer = TimerSet(NULL, 0, 100, EvdevReopenTimer, pInfo);
+    } else
+    {
+        xf86AddEnabledDevice(pInfo);
+        if ((pEvdev->flags & EVDEV_BUTTON_EVENTS) &&
+            !(pEvdev->flags & EVDEV_INITIALIZED))
+        {
+            EvdevMBEmuPreInit(pInfo);
+        }
+        pEvdev->flags |= EVDEV_INITIALIZED;
+        device->public.on = TRUE;
+    }
+
+    return Success;
+}
+
+
 static int
 EvdevProc(DeviceIntPtr device, int what)
 {
@@ -851,30 +961,31 @@ EvdevProc(DeviceIntPtr device, int what)
 	return EvdevInit(device);
 
     case DEVICE_ON:
-        if (!pEvdev->kernel24 && ioctl(pInfo->fd, EVIOCGRAB, (void *)1))
-            xf86Msg(X_WARNING, "%s: Grab failed (%s)\n", pInfo->name,
-                    strerror(errno));
-        if (errno != ENODEV)
-        {
-            xf86AddEnabledDevice(pInfo);
-            if (pEvdev->flags & EVDEV_BUTTON_EVENTS)
-                EvdevMBEmuPreInit(pInfo);
-            device->public.on = TRUE;
-        }
-	break;
+        return EvdevOn(device);
 
     case DEVICE_OFF:
-        if (!pEvdev->kernel24 && ioctl(pInfo->fd, EVIOCGRAB, (void *)0))
-            xf86Msg(X_WARNING, "%s: Release failed (%s)\n", pInfo->name,
-                    strerror(errno));
-        xf86RemoveEnabledDevice(pInfo);
-        EvdevMBEmuFinalize(pInfo);
+        if (pInfo->fd != -1)
+        {
+            if (!pEvdev->kernel24 && ioctl(pInfo->fd, EVIOCGRAB, (void *)0))
+                xf86Msg(X_WARNING, "%s: Release failed (%s)\n", pInfo->name,
+                        strerror(errno));
+            xf86RemoveEnabledDevice(pInfo);
+        }
+        if (pEvdev->flags & EVDEV_INITIALIZED)
+            EvdevMBEmuFinalize(pInfo);
+        pEvdev->flags &= ~EVDEV_INITIALIZED;
 	device->public.on = FALSE;
+        if (pEvdev->reopen_timer)
+        {
+            TimerFree(pEvdev->reopen_timer);
+            pEvdev->reopen_timer = NULL;
+        }
 	break;
 
     case DEVICE_CLOSE:
 	xf86Msg(X_INFO, "%s: Close\n", pInfo->name);
-	close(pInfo->fd);
+        if (pInfo->fd != -1)
+            close(pInfo->fd);
 	break;
     }
 
@@ -904,6 +1015,116 @@ EvdevConvert(InputInfoPtr pInfo, int first, int num, int v0, int v1, int v2,
 
     return TRUE;
 }
+/**
+ * Get as much information as we can from the fd and cache it.
+ * If compare is True, then the information retrieved will be compared to the
+ * one already cached. If the information does not match, then this function
+ * returns an error.
+ *
+ * @return Success if the information was cached, or !Success otherwise.
+ */
+static int
+EvdevCacheCompare(InputInfoPtr pInfo, Bool compare)
+{
+    EvdevPtr pEvdev = pInfo->private;
+    int i;
+
+    char name[1024]                  = {0};
+    long bitmask[NBITS(EV_MAX)]      = {0};
+    long key_bitmask[NBITS(KEY_MAX)] = {0};
+    long rel_bitmask[NBITS(REL_MAX)] = {0};
+    long abs_bitmask[NBITS(ABS_MAX)] = {0};
+    long led_bitmask[NBITS(LED_MAX)] = {0};
+    struct input_absinfo absinfo[ABS_MAX];
+
+    if (ioctl(pInfo->fd,
+              EVIOCGNAME(sizeof(name) - 1), name) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGNAME failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && strcmp(pEvdev->name, name))
+        goto error;
+
+    if (ioctl(pInfo->fd,
+              EVIOCGBIT(0, sizeof(bitmask)), bitmask) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGNAME failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && memcmp(pEvdev->bitmask, bitmask, sizeof(bitmask)))
+        goto error;
+
+
+    if (ioctl(pInfo->fd,
+              EVIOCGBIT(EV_REL, sizeof(rel_bitmask)), rel_bitmask) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGBIT failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && memcmp(pEvdev->rel_bitmask, rel_bitmask, sizeof(rel_bitmask)))
+        goto error;
+
+    if (ioctl(pInfo->fd,
+              EVIOCGBIT(EV_ABS, sizeof(abs_bitmask)), abs_bitmask) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGBIT failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && memcmp(pEvdev->abs_bitmask, abs_bitmask, sizeof(abs_bitmask)))
+        goto error;
+
+    if (ioctl(pInfo->fd,
+              EVIOCGBIT(EV_KEY, sizeof(key_bitmask)), key_bitmask) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGBIT failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && memcmp(pEvdev->key_bitmask, key_bitmask, sizeof(key_bitmask)))
+        goto error;
+
+    if (ioctl(pInfo->fd,
+              EVIOCGBIT(EV_LED, sizeof(led_bitmask)), led_bitmask) < 0) {
+        xf86Msg(X_ERROR, "ioctl EVIOCGBIT failed: %s\n", strerror(errno));
+        goto error;
+    }
+
+    if (compare && memcmp(pEvdev->led_bitmask, led_bitmask, sizeof(led_bitmask)))
+        goto error;
+
+    memset(absinfo, 0, sizeof(absinfo));
+
+    for (i = 0; i < ABS_MAX; i++)
+    {
+        if (TestBit(i, abs_bitmask))
+        {
+            if (ioctl(pInfo->fd, EVIOCGABS(i), &absinfo[i]) < 0) {
+                xf86Msg(X_ERROR, "ioctl EVIOCGABS failed: %s\n", strerror(errno));
+                goto error;
+            }
+        }
+    }
+
+    if (compare && memcmp(pEvdev->absinfo, absinfo, sizeof(absinfo)))
+            goto error;
+
+    /* cache info */
+    if (!compare)
+    {
+        strcpy(pEvdev->name, name);
+        memcpy(pEvdev->bitmask, bitmask, sizeof(bitmask));
+        memcpy(pEvdev->key_bitmask, key_bitmask, sizeof(key_bitmask));
+        memcpy(pEvdev->rel_bitmask, rel_bitmask, sizeof(rel_bitmask));
+        memcpy(pEvdev->abs_bitmask, abs_bitmask, sizeof(abs_bitmask));
+        memcpy(pEvdev->led_bitmask, led_bitmask, sizeof(led_bitmask));
+        memcpy(pEvdev->absinfo, absinfo, sizeof(absinfo));
+    }
+
+    return Success;
+
+error:
+    return !Success;
+}
 
 static int
 EvdevProbe(InputInfoPtr pInfo)
@@ -1060,11 +1281,12 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
         return NULL;
     }
 
+    pEvdev->device = device;
+
     xf86Msg(deviceFrom, "%s: Device: \"%s\"\n", pInfo->name, device);
     do {
         pInfo->fd = open(device, O_RDWR, 0);
-    }
-    while (pInfo->fd < 0 && errno == EINTR);
+    } while (pInfo->fd < 0 && errno == EINTR);
 
     if (pInfo->fd < 0) {
         xf86Msg(X_ERROR, "Unable to open evdev device \"%s\".\n", device);
@@ -1072,6 +1294,8 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
         return NULL;
     }
 
+    pEvdev->reopen_attempts = xf86SetIntOption(pInfo->options, "ReopenAttempts", 10);
+
     pEvdev->noXkb = noXkbExtension;
     /* parse the XKB options during kbd setup */
 
@@ -1081,6 +1305,8 @@ EvdevPreInit(InputDriverPtr drv, IDevPtr dev, int flags)
         return NULL;
     }
 
+    EvdevCacheCompare(pInfo, FALSE); /* cache device data */
+
     return pInfo;
 }
 
diff --git a/src/evdev.h b/src/evdev.h
index cad1eed..9f16b81 100644
--- a/src/evdev.h
+++ b/src/evdev.h
@@ -40,7 +40,11 @@
 #include <X11/extensions/XKBstr.h>
 #endif
 
+#define LONG_BITS (sizeof(long) * 8)
+#define NBITS(x) (((x) + LONG_BITS - 1) / LONG_BITS)
+
 typedef struct {
+    const char *device;
     int kernel24;
     int screen;
     int min_x, min_y, max_x, max_y;
@@ -67,6 +71,18 @@ typedef struct {
         Time                expires;     /* time of expiry */
         Time                timeout;
     } emulateMB;
+    int reopen_attempts; /* max attempts to re-open after read failure */
+    int reopen_left;     /* number of attempts left to re-open the device */
+    OsTimerPtr reopen_timer;
+
+    /* Cached info from device. */
+    char name[1024];
+    long bitmask[NBITS(EV_MAX)];
+    long key_bitmask[NBITS(KEY_MAX)];
+    long rel_bitmask[NBITS(REL_MAX)];
+    long abs_bitmask[NBITS(ABS_MAX)];
+    long led_bitmask[NBITS(LED_MAX)];
+    struct input_absinfo absinfo[ABS_MAX];
 } EvdevRec, *EvdevPtr;
 
 /* Middle Button emulation */