linux-kernel - [PATCH] drm/bridge: Fix Exynos DSI after making bridge chain a double-linked list

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Message-Id: <20191227110135.4961-1-m.szyprowski@samsung.com>
Date:   Fri, 27 Dec 2019 12:01:35 +0100
From:   Marek Szyprowski <m.szyprowski@...sung.com>
To:     dri-devel@...ts.freedesktop.org, linux-samsung-soc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Marek Szyprowski <m.szyprowski@...sung.com>,
        Inki Dae <inki.dae@...sung.com>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Boris Brezillon <boris.brezillon@...labora.com>,
        Krzysztof Kozlowski <krzk@...nel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>,
        Neil Armstrong <narmstrong@...libre.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Thierry Reding <thierry.reding@...il.com>
Subject: [PATCH] drm/bridge: Fix Exynos DSI after making bridge chain a
 double-linked list

Exynos DSI DRM driver uses private calls to out bridge to force certain
order of operations during init/exit sequences. This no longer works after
conversion of bridge chain to a double-linked list. To fix the regression
call bridge related operations manually instead of the generic
drm_bridge_chain_*() operations.

Signed-off-by: Marek Szyprowski <m.szyprowski@...sung.com>
Fixes: 05193dc38197 ("drm/bridge: Make the bridge chain a double-linked list")
---
This patch is a result of the following discussion:
https://www.spinics.net/lists/dri-devel/msg239256.html
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 21 ++++++++++++---------
 1 file changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 3955f84dc893..f5905c239a86 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -255,7 +255,6 @@ struct exynos_dsi {
 	struct mipi_dsi_host dsi_host;
 	struct drm_connector connector;
 	struct drm_panel *panel;
-	struct list_head bridge_chain;
 	struct drm_bridge *out_bridge;
 	struct device *dev;
 
@@ -1391,7 +1390,8 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
 		if (ret < 0)
 			goto err_put_sync;
 	} else {
-		drm_bridge_chain_pre_enable(dsi->out_bridge);
+		if (dsi->out_bridge->funcs->pre_enable)
+			dsi->out_bridge->funcs->pre_enable(dsi->out_bridge);
 	}
 
 	exynos_dsi_set_display_mode(dsi);
@@ -1402,7 +1402,8 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)
 		if (ret < 0)
 			goto err_display_disable;
 	} else {
-		drm_bridge_chain_enable(dsi->out_bridge);
+		if (dsi->out_bridge->funcs->enable)
+			dsi->out_bridge->funcs->enable(dsi->out_bridge);
 	}
 
 	dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE;
@@ -1427,10 +1428,12 @@ static void exynos_dsi_disable(struct drm_encoder *encoder)
 	dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;
 
 	drm_panel_disable(dsi->panel);
-	drm_bridge_chain_disable(dsi->out_bridge);
+	if (dsi->out_bridge->funcs->disable)
+		dsi->out_bridge->funcs->disable(dsi->out_bridge);
 	exynos_dsi_set_display_enable(dsi, false);
 	drm_panel_unprepare(dsi->panel);
-	drm_bridge_chain_post_disable(dsi->out_bridge);
+	if (dsi->out_bridge->funcs->post_disable)
+		dsi->out_bridge->funcs->post_disable(dsi->out_bridge);
 	dsi->state &= ~DSIM_STATE_ENABLED;
 	pm_runtime_put_sync(dsi->dev);
 }
@@ -1521,9 +1524,11 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 
 	out_bridge  = of_drm_find_bridge(device->dev.of_node);
 	if (out_bridge) {
-		drm_bridge_attach(encoder, out_bridge, NULL);
+		out_bridge->dev = drm;
+		out_bridge->encoder = encoder;
+		if (out_bridge->funcs->attach)
+			out_bridge->funcs->attach(out_bridge);
 		dsi->out_bridge = out_bridge;
-		list_splice(&encoder->bridge_chain, &dsi->bridge_chain);
 	} else {
 		int ret = exynos_dsi_create_connector(encoder);
 
@@ -1589,7 +1594,6 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
 		if (dsi->out_bridge->funcs->detach)
 			dsi->out_bridge->funcs->detach(dsi->out_bridge);
 		dsi->out_bridge = NULL;
-		INIT_LIST_HEAD(&dsi->bridge_chain);
 	}
 
 	if (drm->mode_config.poll_enabled)
@@ -1737,7 +1741,6 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 	init_completion(&dsi->completed);
 	spin_lock_init(&dsi->transfer_lock);
 	INIT_LIST_HEAD(&dsi->transfer_list);
-	INIT_LIST_HEAD(&dsi->bridge_chain);
 
 	dsi->dsi_host.ops = &exynos_dsi_ops;
 	dsi->dsi_host.dev = dev;
-- 
2.17.1