On Tue, Jul 16, 2019 at 10:08:28AM -0600, Ross Zwisler wrote:
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
Thank you for the explanation. I've queued both this and the 4.19 patches, and added your explanation to the 4.14 patch.
-- Thanks, Sasha