diff --git a/sys/dev/drm/drmP.h b/sys/dev/drm/drmP.h
index af50893..3ae7d9f 100644
--- a/sys/dev/drm/drmP.h
+++ b/sys/dev/drm/drmP.h
@@ -93,6 +93,7 @@ struct drm_file;
 #endif /* __FreeBSD_version >= 800004 */
 #include <sys/agpio.h>
 #include <sys/mutex.h>
+#include <sys/sx.h>
 #include <dev/pci/pcivar.h>
 #include <dev/pci/pcireg.h>
 #include <sys/selinfo.h>
@@ -192,10 +193,10 @@ SYSCTL_DECL(_hw_drm);
 	(void)irqflags;					\
 } while (0)
 #define DRM_SPINUNLOCK_IRQRESTORE(u, irqflags) mtx_unlock(u)
-#define DRM_SPINLOCK_ASSERT(l)	mtx_assert(l, MA_OWNED)
+#define DRM_SPINLOCK_ASSERT(l)	sx_assert(l, MA_OWNED)
 #define DRM_CURRENTPID		curthread->td_proc->p_pid
-#define DRM_LOCK()		mtx_lock(&dev->dev_lock)
-#define DRM_UNLOCK() 		mtx_unlock(&dev->dev_lock)
+#define DRM_LOCK()		sx_xlock(&dev->dev_lock)
+#define DRM_UNLOCK() 		sx_xunlock(&dev->dev_lock)
 #define DRM_SYSCTL_HANDLER_ARGS	(SYSCTL_HANDLER_ARGS)
 
 #define DRM_IRQ_ARGS		void *arg
@@ -630,7 +631,7 @@ struct drm_device {
 	struct mtx	  vbl_lock;	/* protects vblank operations */
 	struct mtx	  dma_lock;	/* protects dev->dma */
 	struct mtx	  irq_lock;	/* protects irq condition checks */
-	struct mtx	  dev_lock;	/* protects everything else */
+	struct sx	  dev_lock;	/* protects everything else */
 	DRM_SPINTYPE	  drw_lock;
 
 				/* Usage Counters */
diff --git a/sys/dev/drm/drm_drv.c b/sys/dev/drm/drm_drv.c
index 8d9bc69..7d2cfa1 100644
--- a/sys/dev/drm/drm_drv.c
+++ b/sys/dev/drm/drm_drv.c
@@ -254,7 +254,7 @@ int drm_attach(device_t kdev, drm_pci_id_list_t *idlist)
 		dev->irq = (int) rman_get_start(dev->irqr);
 	}
 
-	mtx_init(&dev->dev_lock, "drmdev", NULL, MTX_DEF);
+	sx_init(&dev->dev_lock, "drmdev");
 	mtx_init(&dev->irq_lock, "drmirq", NULL, MTX_DEF);
 	mtx_init(&dev->vbl_lock, "drmvbl", NULL, MTX_DEF);
 	mtx_init(&dev->drw_lock, "drmdrw", NULL, MTX_DEF);
@@ -516,7 +516,7 @@ error:
 	mtx_destroy(&dev->drw_lock);
 	mtx_destroy(&dev->vbl_lock);
 	mtx_destroy(&dev->irq_lock);
-	mtx_destroy(&dev->dev_lock);
+	sx_destroy(&dev->dev_lock);
 
 	return retcode;
 }
@@ -581,7 +581,7 @@ static void drm_unload(struct drm_device *dev)
 	mtx_destroy(&dev->drw_lock);
 	mtx_destroy(&dev->vbl_lock);
 	mtx_destroy(&dev->irq_lock);
-	mtx_destroy(&dev->dev_lock);
+	sx_destroy(&dev->dev_lock);
 }
 
 int drm_version(struct drm_device *dev, void *data, struct drm_file *file_priv)
@@ -683,7 +683,7 @@ void drm_close(void *data)
 				break;	/* Got lock */
 			}
 			/* Contention */
-			retcode = mtx_sleep((void *)&dev->lock.lock_queue,
+			retcode = sx_sleep((void *)&dev->lock.lock_queue,
 			    &dev->dev_lock, PCATCH, "drmlk2", 0);
 			if (retcode)
 				break;
diff --git a/sys/dev/drm/drm_lock.c b/sys/dev/drm/drm_lock.c
index 28573c8..0b6bd82 100644
--- a/sys/dev/drm/drm_lock.c
+++ b/sys/dev/drm/drm_lock.c
@@ -81,7 +81,7 @@ int drm_lock(struct drm_device *dev, void *data, struct drm_file *file_priv)
 		}
 
 		/* Contention */
-		ret = mtx_sleep((void *)&dev->lock.lock_queue, &dev->dev_lock,
+		ret = sx_sleep((void *)&dev->lock.lock_queue, &dev->dev_lock,
 		    PCATCH, "drmlk2", 0);
 		if (ret != 0)
 			break;
diff --git a/sys/dev/drm/drm_pci.c b/sys/dev/drm/drm_pci.c
index afd6604..815eb3f 100644
--- a/sys/dev/drm/drm_pci.c
+++ b/sys/dev/drm/drm_pci.c
@@ -72,8 +72,8 @@ drm_pci_alloc(struct drm_device *dev, size_t size,
 		return NULL;
 
 	/* Make sure we aren't holding locks here */
-	mtx_assert(&dev->dev_lock, MA_NOTOWNED);
-	if (mtx_owned(&dev->dev_lock))
+	sx_assert(&dev->dev_lock, MA_NOTOWNED);
+	if (sx_xlocked(&dev->dev_lock))
 	    DRM_ERROR("called while holding dev_lock\n");
 	mtx_assert(&dev->dma_lock, MA_NOTOWNED);
 	if (mtx_owned(&dev->dma_lock))
diff --git a/sys/dev/drm/radeon_cp.c b/sys/dev/drm/radeon_cp.c
index 0a486af..2dbde73 100644
--- a/sys/dev/drm/radeon_cp.c
+++ b/sys/dev/drm/radeon_cp.c
@@ -1697,13 +1697,13 @@ void radeon_do_release(struct drm_device * dev)
 			if ((dev_priv->flags & RADEON_FAMILY_MASK) >= CHIP_R600) {
 				while ((ret = r600_do_cp_idle(dev_priv)) != 0) {
 					DRM_DEBUG("radeon_do_cp_idle %d\n", ret);
-					mtx_sleep(&ret, &dev->dev_lock, 0,
+					sx_sleep(&ret, &dev->dev_lock, 0,
 					    "rdnrel", 1);
 				}
 			} else {
 				while ((ret = radeon_do_cp_idle(dev_priv)) != 0) {
 					DRM_DEBUG("radeon_do_cp_idle %d\n", ret);
-					mtx_sleep(&ret, &dev->dev_lock, 0,
+					sx_sleep(&ret, &dev->dev_lock, 0,
 					    "rdnrel", 1);
 				}
 			}