xf86: don't hotplug output devices while VT switched.

We don't want to hotplug output devices while we are VT switched,
as we get races between multiple X servers on the device open, and
drm device master status. This just queues device opens until we return
from VT switch.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Dave Airlie <airlied@redhat.com>

hw/xfree86/common/xf86Events.c

@@ -84,6 +84,7 @@
 #include "dpmsproc.h"
 #endif
 
+#include "xf86platformBus.h"
 /*
  * This is a toggling variable:
  *  FALSE = No VT switching keys have been pressed last time around
@@ -560,6 +561,9 @@ xf86VTSwitch(void)
         for (ih = InputHandlers; ih; ih = ih->next)
             xf86EnableInputHandler(ih);
 
+        /* check for any new output devices */
+        xf86platformVTProbe();
+
         OsReleaseSIGIO();
     }
 }

hw/xfree86/common/xf86platformBus.c

@@ -113,6 +113,11 @@ xf86_get_platform_device_attrib(struct xf86_platform_device *device, int attrib_
     return NULL;
 }
 
+Bool
+xf86_get_platform_device_unowned(int index)
+{
+    return xf86_platform_devices[index].attribs->unowned;
+}
 
 /*
  * xf86IsPrimaryPlatform() -- return TRUE if primary device
@@ -498,4 +503,18 @@ xf86platformRemoveDevice(int index)
  out:
     return;
 }
+
+/* called on return from VT switch to find any new devices */
+void xf86platformVTProbe(void)
+{
+    int i;
+
+    for (i = 0; i < xf86_num_platform_devices; i++) {
+        if (xf86_platform_devices[i].attribs->unowned == FALSE)
+            continue;
+
+        xf86_platform_devices[i].attribs->unowned = FALSE;
+        xf86PlatformReprobeDevice(i, xf86_platform_devices[i].attribs);
+    }
+}
 #endif

hw/xfree86/common/xf86platformBus.h

@@ -46,6 +46,8 @@ extern int
 xf86_remove_platform_device(int dev_index);
 extern Bool
 xf86_add_platform_device_attrib(int index, int attrib_id, char *attrib_str);
+extern Bool
+xf86_get_platform_device_unowned(int index);
 
 extern int
 xf86platformAddDevice(int index);
@@ -59,6 +61,8 @@ xf86PlatformDeviceCheckBusID(struct xf86_platform_device *device, const char *bu
 
 extern _X_EXPORT int
 xf86PlatformMatchDriver(char *matches[], int nmatches);
+
+extern void xf86platformVTProbe(void);
 #endif
 
 #endif

hw/xfree86/os-support/linux/lnx_platform.c

@@ -20,7 +20,7 @@
 #include "hotplug.h"
 
 static Bool
-get_drm_info(struct OdevAttributes *attribs, char *path)
+get_drm_info(struct OdevAttributes *attribs, char *path, int delayed_index)
 {
     drmSetVersion sv;
     char *buf;
@@ -60,10 +60,14 @@ get_drm_info(struct OdevAttributes *attribs, char *path)
 	goto out;
     }
 
-    xf86_add_platform_device(attribs);
+    /* for a delayed probe we've already added the device */
+    if (delayed_index == -1) {
+            xf86_add_platform_device(attribs);
+            delayed_index = xf86_num_platform_devices - 1;
+    }
 
     buf = drmGetBusid(fd);
-    xf86_add_platform_device_attrib(xf86_num_platform_devices - 1,
+    xf86_add_platform_device_attrib(delayed_index,
                                     ODEV_ATTRIB_BUSID, buf);
     drmFreeBusid(buf);
 out:
@@ -112,6 +116,23 @@ xf86PlatformDeviceCheckBusID(struct xf86_platform_device *device, const char *bu
     return FALSE;
 }
 
+void
+xf86PlatformReprobeDevice(int index, struct OdevAttributes *attribs)
+{
+    Bool ret;
+    char *dpath;
+    dpath = xf86_get_platform_attrib(index, ODEV_ATTRIB_PATH);
+
+    ret = get_drm_info(attribs, dpath, index);
+    if (ret == FALSE) {
+        xf86_remove_platform_device(index);
+        return;
+    }
+    ret = xf86platformAddDevice(index);
+    if (ret == -1)
+        xf86_remove_platform_device(index);
+}
+
 void
 xf86PlatformDeviceProbe(struct OdevAttributes *attribs)
 {
@@ -143,7 +164,15 @@ xf86PlatformDeviceProbe(struct OdevAttributes *attribs)
     LogMessage(X_INFO, "config/udev: Adding drm device (%s)\n",
                path);
 
-    ret = get_drm_info(attribs, path);
+    if (!xf86VTOwner()) {
+            /* if we don't currently own the VT then don't probe the device,
+               just mark it as unowned for later use */
+            attribs->unowned = TRUE;
+            xf86_add_platform_device(attribs);
+            return;
+    }
+
+    ret = get_drm_info(attribs, path, -1);
     if (ret == FALSE)
         goto out_free;
 
@@ -162,6 +191,9 @@ void NewGPUDeviceRequest(struct OdevAttributes *attribs)
     if (old_num == xf86_num_platform_devices)
         return;
 
+    if (xf86_get_platform_device_unowned(xf86_num_platform_devices - 1) == TRUE)
+        return;
+
     ret = xf86platformAddDevice(xf86_num_platform_devices-1);
     if (ret == -1)
         xf86_remove_platform_device(xf86_num_platform_devices-1);
@@ -195,7 +227,10 @@ void DeleteGPUDeviceRequest(struct OdevAttributes *attribs)
 
     ErrorF("xf86: remove device %d %s\n", index, syspath);
 
-    xf86platformRemoveDevice(index);
+    if (xf86_get_platform_device_unowned(index) == TRUE)
+            xf86_remove_platform_device(index);
+    else
+            xf86platformRemoveDevice(index);
 out:
     config_odev_free_attribute_list(attribs);
 }

hw/xfree86/os-support/xf86_OSproc.h

@@ -223,6 +223,9 @@ extern _X_EXPORT void xf86InitVidMem(void);
 #include "hotplug.h"
 void
 xf86PlatformDeviceProbe(struct OdevAttributes *attribs);
+
+void
+xf86PlatformReprobeDevice(int index, struct OdevAttributes *attribs);
 #endif
 
 _XFUNCPROTOEND

include/hotplug.h

@@ -40,6 +40,7 @@ struct OdevAttribute {
 
 struct OdevAttributes {
     struct xorg_list list;
+    Bool unowned;
 };
 
 struct OdevAttributes *