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Commit 759d706f authored by Thierry Reding's avatar Thierry Reding
Browse files

drm/tegra: dc: Do not register DC without primary plane 



Tegra194 contains a fourth display controller that does not own any
windows. Therefore, we cannot currently assign a primary plane to it
which causes KMS to eventually crash. Do not register the display
controller if it owns no windows to work around this.

Note that we still have to enable and probe the display controller
because for some reason all display controllers need to be powered
(and/or clocked) before any registers can be accessed in any of the
display controllers.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
parent 47022003

drivers/gpu/drm/tegra/dc.c

+22 −0
Original line number Diff line number Diff line
@@ -1988,6 +1988,28 @@ static int tegra_dc_init(struct host1x_client *client) 
	struct drm_plane *cursor = NULL;

	int err;



	/*

	 * XXX do not register DCs with no window groups because we cannot

	 * assign a primary plane to them, which in turn will cause KMS to

	 * crash.

	 */

	if (dc->soc->wgrps) {

		bool has_wgrps = false;

		unsigned int i;



		for (i = 0; i < dc->soc->num_wgrps; i++) {

			const struct tegra_windowgroup_soc *wgrp = &dc->soc->wgrps[i];



			if (wgrp->dc == dc->pipe && wgrp->num_windows > 0) {

				has_wgrps = true;

				break;

			}

		}



		if (!has_wgrps)

			return 0;

	}



	dc->syncpt = host1x_syncpt_request(client, flags);

	if (!dc->syncpt)

		dev_warn(dc->dev, "failed to allocate syncpoint\n");