Commit a31500fe authored by Thierry Reding's avatar Thierry Reding
Browse files

drm/tegra: dc: Restore coupling of display controllers 



Coupling of display controllers used to rely on runtime PM to take the
companion controller out of reset. Commit fd67e9c6 ("drm/tegra: Do
not implement runtime PM") accidentally broke this when runtime PM was
removed.

Restore this functionality by reusing the hierarchical host1x client
suspend/resume infrastructure that's similar to runtime PM and which
perfectly fits this use-case.

Fixes: fd67e9c6 ("drm/tegra: Do not implement runtime PM")
Reported-by: default avatarDmitry Osipenko <digetx@gmail.com>
Reported-by: default avatarPaul Fertser <fercerpav@gmail.com>
Tested-by: default avatarDmitry Osipenko <digetx@gmail.com>
Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent a24f9817

drivers/gpu/drm/tegra/dc.c

+8 −12
Original line number Diff line number Diff line
@@ -2501,22 +2501,18 @@ static int tegra_dc_couple(struct tegra_dc *dc) 
	 * POWER_CONTROL registers during CRTC enabling.

	 */

	if (dc->soc->coupled_pm && dc->pipe == 1) {

		u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER;

		struct device_link *link;

		struct device *partner;

		struct device *companion;

		struct tegra_dc *parent;



		partner = driver_find_device(dc->dev->driver, NULL, NULL,

		companion = driver_find_device(dc->dev->driver, NULL, (const void *)0,

					       tegra_dc_match_by_pipe);

		if (!partner)

		if (!companion)

			return -EPROBE_DEFER;



		link = device_link_add(dc->dev, partner, flags);

		if (!link) {

			dev_err(dc->dev, "failed to link controllers\n");

			return -EINVAL;

		}

		parent = dev_get_drvdata(companion);

		dc->client.parent = &parent->client;



		dev_dbg(dc->dev, "coupled to %s\n", dev_name(partner));

		dev_dbg(dc->dev, "coupled to %s\n", dev_name(companion));

	}



	return 0;