Hi Laurent,
On Sun, Jun 07, 2020 at 05:41:58AM +0300, Laurent Pinchart wrote:
Note that the CMM driver is controlled by the DU driver. As the DU driver will reenable the display during resume, it will call rcar_du_cmm_setup() at resume time, which will reprogram the CMM. There should thus be no need for manual suspend/resume handling in the CMM as far as I can tell, but we need to ensure that the CMM is suspended before and resumed after the DU. I believe this could be implemented using device links.
Based on below quote [*] from Jacopo's commit [**], isn't the device link relationship already in place?
[*] Quote from commit [**] Enforce the probe and suspend/resume ordering of DU and CMM by creating a stateless device link between the two.
[**] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... ("drm: rcar-du: kms: Initialize CMM instances")