Module Name: src
Committed By: riastradh
Date: Sat Apr 2 22:40:43 UTC 2016
Modified Files:
src/sys/external/bsd/drm2/drm: drm_lock.c
Log Message:
Take a stab at implementing drm_idlelock_take/release.
Evidently needed by VIA DRM/UMS. Noted and tested by medfly/coypu.
To generate a diff of this commit:
cvs rdiff -u -r1.3 -r1.4 src/sys/external/bsd/drm2/drm/drm_lock.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/external/bsd/drm2/drm/drm_lock.c
diff -u src/sys/external/bsd/drm2/drm/drm_lock.c:1.3 src/sys/external/bsd/drm2/drm/drm_lock.c:1.4
--- src/sys/external/bsd/drm2/drm/drm_lock.c:1.3 Wed Jul 16 20:56:25 2014
+++ src/sys/external/bsd/drm2/drm/drm_lock.c Sat Apr 2 22:40:43 2016
@@ -1,4 +1,4 @@
-/* $NetBSD: drm_lock.c,v 1.3 2014/07/16 20:56:25 riastradh Exp $ */
+/* $NetBSD: drm_lock.c,v 1.4 2016/04/02 22:40:43 riastradh Exp $ */
/*-
* Copyright (c) 2013 The NetBSD Foundation, Inc.
@@ -46,7 +46,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: drm_lock.c,v 1.3 2014/07/16 20:56:25 riastradh Exp $");
+__KERNEL_RCSID(0, "$NetBSD: drm_lock.c,v 1.4 2016/04/02 22:40:43 riastradh Exp $");
#include <sys/types.h>
#include <sys/errno.h>
@@ -232,28 +232,47 @@ drm_lock_free(struct drm_lock_data *lock
}
/*
- * Take the lock for the kernel's use.
- *
- * XXX This is unimplemented because it's not clear that the Linux code
- * makes sense at all. Linux's drm_idlelock_take never blocks, but it
- * doesn't guarantee that the kernel holds the lock on return! For
- * now, I'll hope that the code paths relying on this don't matter yet.
+ * Try to acquire the lock. Whether or not we acquire it, guarantee
+ * that whoever next releases it relinquishes it to the kernel, not to
+ * anyone else.
*/
void
-drm_idlelock_take(struct drm_lock_data *lock_data __unused)
+drm_idlelock_take(struct drm_lock_data *lock_data)
{
- KASSERT(mutex_is_locked(&drm_global_mutex));
- panic("drm_idlelock_take is not yet implemented"); /* XXX */
+
+ spin_lock(&lock_data->spinlock);
+ KASSERT(!lock_data->idle_has_lock);
+ KASSERT(lock_data->kernel_waiters < UINT32_MAX);
+ lock_data->kernel_waiters++;
+ /* Try to acquire the lock. */
+ if (drm_lock_acquire(lock_data, DRM_KERNEL_CONTEXT)) {
+ lock_data->idle_has_lock = 1;
+ } else {
+ /*
+ * Recording that there are kernel waiters will prevent
+ * userland from acquiring the lock again when it is
+ * next released.
+ */
+ }
+ spin_unlock(&lock_data->spinlock);
}
/*
- * Release the lock from the kernel.
+ * Release whatever drm_idlelock_take managed to acquire.
*/
void
-drm_idlelock_release(struct drm_lock_data *lock_data __unused)
+drm_idlelock_release(struct drm_lock_data *lock_data)
{
- KASSERT(mutex_is_locked(&drm_global_mutex));
- panic("drm_idlelock_release is not yet implemented"); /* XXX */
+
+ spin_lock(&lock_data->spinlock);
+ KASSERT(0 < lock_data->kernel_waiters);
+ if (--lock_data->kernel_waiters == 0) {
+ if (lock_data->idle_has_lock) {
+ /* We did acquire it. Release it. */
+ drm_lock_release(lock_data, DRM_KERNEL_CONTEXT);
+ }
+ }
+ spin_unlock(&lock_data->spinlock);
}
/*
