[PATCH] Documentation: vkms: clarify devres managed refernce cleanup

[Brandon Pollack]

added documentation to drm_dev_unregister clarifying that devres managed
devices allocated with devm_drm_dev_alloc do not require calls to
drm_dev_put.

Signed-off-by: Brandon Pollack <brpol at chromium.org>

---

This is my first patch to any tree.  I've tried my best to read as many
kernel docs etc as possible (wip). This took me a moment to realize so I
figured it was as good a candidate as any for a first patch (at the very
least to make sure I have the whole patching process figured out).  I
hope to make more janitorial changes as I continue to learn leading up
to the work I hope to do.

We're hoping to add multiple display hotplug output support to VKMS for
testing purposes.  Some work has been done already, but we'll be taking
over moving forward.  Our intent is to remain involved and assist in
maintaining these changes.

Looking forward to your comments/advice (now and henceforth!)
---
 drivers/gpu/drm/drm_drv.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index cee0cc522ed9..12687dd9e1ac 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -969,7 +969,9 @@ EXPORT_SYMBOL(drm_dev_register);
  *
  * Unregister the DRM device from the system. This does the reverse of
  * drm_dev_register() but does not deallocate the device. The caller must call
- * drm_dev_put() to drop their final reference.
+ * drm_dev_put() to drop their final reference, unless it is managed with devres
+ * (as devices allocated with devm_drm_dev_alloc() are), in which case there is
+ * already an unwind action registered.
  *
  * A special form of unregistering for hotpluggable devices is drm_dev_unplug(),
  * which can be called while there are still open users of @dev.
-- 
2.40.0.634.g4ca3ef3211-goog