On Mon, Jul 15, 2019 at 09:13:08PM -0400, Sasha Levin wrote:
> On Mon, Jul 15, 2019 at 01:36:16PM -0600, Ross Zwisler wrote:
> > This patch is the second in this series, and requires the first patch as
> > a dependency. This series apples cleanly to v4.14.133.
>
> Hm, we don't need ac3b35f11a06 here? Why not? I'd love to document that
> with the backport.
Nope, we don't need that patch in the v4.14 backport.
In v4.19.y we have two functions, drm_dev_put() and drm_dev_unref(), which are
aliases for one another (drm_dev_unref() just calls drm_dev_put()).
drm_dev_unref() is the older of the two, and was introduced back in v4.0.
drm_dev_put() was introduced in v4.15 with
9a96f55034e41 drm: introduce drm_dev_{get/put} functions
and slowly callers were moved from the old name (_unref) to the new name
(_put). The patch you mentioned, ac3b35f11a06, is one such patch where we are
replacing a drm_dev_unref() call with a drm_dev_put() call. This doesn't have
a functional change, but was necessary so that the third patch in the v4.19.y
series I sent would apply cleanly.
For the v4.14.y series, though, the drm_dev_put() function hasn't yet been
defined and everyone is still using drm_dev_unref(). So, we don't need a
backport of ac3b35f11a06, and I also had a small backport change in the last
patch of the v4.14.y series where I had to change a drm_dev_put() call with a
drm_dev_unref() call.
Just for posterity, the drm_dev_unref() calls were eventually all changed to
drm_dev_put() in v5.0, and drm_dev_unref() was removed entirely. That
happened with the following two patches:
808bad32ea423 drm: replace "drm_dev_unref" function with "drm_dev_put"
ba1d345401476 drm: remove deprecated "drm_dev_unref" function
