[PATCH 4/5] drm: add core support for unplugging a device

[Dave Airlie]

From: Dave Airlie <airlied at redhat.com>

Two parts to this, one is simple unplug from sysfs for the device node.

The second adds an unplugged state, if we have device opens, we
just set the unplugged state and return, if we have no device
opens we drop the drm device.

If after a lastclose we discover we are unplugged we then
drop the drm device.

Signed-off-by: Dave Airlie <airlied at redhat.com>
---
 drivers/gpu/drm/drm_fops.c |    2 ++
 drivers/gpu/drm/drm_stub.c |   22 ++++++++++++++++++++++
 include/drm/drmP.h         |    2 ++
 3 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/drm_fops.c b/drivers/gpu/drm/drm_fops.c
index 6263b01..154cfac 100644
--- a/drivers/gpu/drm/drm_fops.c
+++ b/drivers/gpu/drm/drm_fops.c
@@ -579,6 +579,8 @@ int drm_release(struct inode *inode, struct file *filp)
 			retcode = -EBUSY;
 		} else
 			retcode = drm_lastclose(dev);
+		if (dev->unplugged)
+			drm_put_dev(dev);
 	}
 	mutex_unlock(&drm_global_mutex);
 
diff --git a/drivers/gpu/drm/drm_stub.c b/drivers/gpu/drm/drm_stub.c
index 6d7b083..b04c92d 100644
--- a/drivers/gpu/drm/drm_stub.c
+++ b/drivers/gpu/drm/drm_stub.c
@@ -429,6 +429,11 @@ int drm_put_minor(struct drm_minor **minor_p)
 	return 0;
 }
 
+static void drm_unplug_minor(struct drm_minor *minor)
+{
+	drm_sysfs_device_remove(minor);
+}
+
 /**
  * Called via drm_exit() at module unload time or when pci device is
  * unplugged.
@@ -492,3 +497,20 @@ void drm_put_dev(struct drm_device *dev)
 	kfree(dev);
 }
 EXPORT_SYMBOL(drm_put_dev);
+
+void drm_unplug_dev(struct drm_device *dev)
+{
+	/* for a USB device */
+	if (drm_core_check_feature(dev, DRIVER_MODESET))
+		drm_unplug_minor(dev->control);
+	drm_unplug_minor(dev->primary);
+
+	dev->unplugged = true;
+
+	mutex_lock(&drm_global_mutex);
+	if (dev->open_count == 0) {
+		drm_put_dev(dev);
+	}
+	mutex_unlock(&drm_global_mutex);
+}
+EXPORT_SYMBOL(drm_unplug_dev);
diff --git a/include/drm/drmP.h b/include/drm/drmP.h
index 92f0981..8c11797 100644
--- a/include/drm/drmP.h
+++ b/include/drm/drmP.h
@@ -1170,6 +1170,7 @@ struct drm_device {
 	struct idr object_name_idr;
 	/*@} */
 	int switch_power_state;
+	bool unplugged; /* device has been unplugged or gone away */
 };
 
 #define DRM_SWITCH_POWER_ON 0
@@ -1464,6 +1465,7 @@ extern void drm_master_put(struct drm_master **master);
 
 extern void drm_put_dev(struct drm_device *dev);
 extern int drm_put_minor(struct drm_minor **minor);
+extern void drm_unplug_dev(struct drm_device *dev);
 extern unsigned int drm_debug;
 
 extern unsigned int drm_vblank_offdelay;
-- 
1.7.6