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* [PATCH 1/5] drm/tegra: dc: Do not register DC without primary plane
@ 2018-09-21 10:27 Thierry Reding
  2018-09-21 10:27 ` [PATCH 2/5] drm/tegra: hub: Add Tegra194 support Thierry Reding
                   ` (3 more replies)
  0 siblings, 4 replies; 5+ messages in thread
From: Thierry Reding @ 2018-09-21 10:27 UTC (permalink / raw)
  To: Thierry Reding; +Cc: linux-tegra, dri-devel

From: Thierry Reding <treding@nvidia.com>

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: Thierry Reding <treding@nvidia.com>
---
 drivers/gpu/drm/tegra/dc.c | 22 ++++++++++++++++++++++
 1 file changed, 22 insertions(+)

diff --git a/drivers/gpu/drm/tegra/dc.c b/drivers/gpu/drm/tegra/dc.c
index 965088afcfad..7e36ca204cbb 100644
--- a/drivers/gpu/drm/tegra/dc.c
+++ b/drivers/gpu/drm/tegra/dc.c
@@ -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");
-- 
2.19.0

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^ permalink raw reply related	[flat|nested] 5+ messages in thread

end of thread, other threads:[~2018-09-21 10:27 UTC | newest]

Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-09-21 10:27 [PATCH 1/5] drm/tegra: dc: Do not register DC without primary plane Thierry Reding
2018-09-21 10:27 ` [PATCH 2/5] drm/tegra: hub: Add Tegra194 support Thierry Reding
2018-09-21 10:27 ` [PATCH 3/5] drm/tegra: dc: " Thierry Reding
2018-09-21 10:27 ` [PATCH 4/5] drm/tegra: dpaux: " Thierry Reding
2018-09-21 10:27 ` [PATCH 5/5] drm/tegra: sor: " Thierry Reding

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