On D3 and E3 platforms, the LVDS encoder includes a PLL that can
generate a clock for the corresponding CRTC, used even when the CRTC
output to a non-LVDS port. This mechanism is supported by the driver,
but the implementation is broken in dual-link LVDS mode. In that case,
the LVDS1 drm_encoder is skipped, which causes a crash when trying to
access its bridge later on.

Fix this by storing bridge pointers internally instead of retrieving
them from the encoder.

Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
 drivers/gpu/drm/rcar-du/rcar_du_crtc.c    | 10 ++--------
 drivers/gpu/drm/rcar-du/rcar_du_drv.h     |  3 +++
 drivers/gpu/drm/rcar-du/rcar_du_encoder.c |  4 ++++
 3 files changed, 9 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c 
b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
index b5fb941e0f53..e23b9c7b4afe 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_crtc.c
@@ -730,13 +730,10 @@ static void rcar_du_crtc_atomic_enable(struct drm_crtc 
*crtc,
         */
        if (rcdu->info->lvds_clk_mask & BIT(rcrtc->index) &&
            rstate->outputs == BIT(RCAR_DU_OUTPUT_DPAD0)) {
-               struct rcar_du_encoder *encoder =
-                       rcdu->encoders[RCAR_DU_OUTPUT_LVDS0 + rcrtc->index];
+               struct drm_bridge *bridge = rcdu->lvds[rcrtc->index];
                const struct drm_display_mode *mode =
                        &crtc->state->adjusted_mode;
-               struct drm_bridge *bridge;
 
-               bridge = drm_bridge_chain_get_first_bridge(&encoder->base);
                rcar_lvds_clk_enable(bridge, mode->clock * 1000);
        }
 
@@ -764,15 +761,12 @@ static void rcar_du_crtc_atomic_disable(struct drm_crtc 
*crtc,
 
        if (rcdu->info->lvds_clk_mask & BIT(rcrtc->index) &&
            rstate->outputs == BIT(RCAR_DU_OUTPUT_DPAD0)) {
-               struct rcar_du_encoder *encoder =
-                       rcdu->encoders[RCAR_DU_OUTPUT_LVDS0 + rcrtc->index];
-               struct drm_bridge *bridge;
+               struct drm_bridge *bridge = rcdu->lvds[rcrtc->index];
 
                /*
                 * Disable the LVDS clock output, see
                 * rcar_du_crtc_atomic_enable().
                 */
-               bridge = drm_bridge_chain_get_first_bridge(&encoder->base);
                rcar_lvds_clk_disable(bridge);
        }
 
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.h 
b/drivers/gpu/drm/rcar-du/rcar_du_drv.h
index 61504c54e2ec..71732fc5df8f 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_drv.h
+++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.h
@@ -20,6 +20,7 @@
 
 struct clk;
 struct device;
+struct drm_bridge;
 struct drm_device;
 struct drm_property;
 struct rcar_du_device;
@@ -71,6 +72,7 @@ struct rcar_du_device_info {
 #define RCAR_DU_MAX_CRTCS              4
 #define RCAR_DU_MAX_GROUPS             DIV_ROUND_UP(RCAR_DU_MAX_CRTCS, 2)
 #define RCAR_DU_MAX_VSPS               4
+#define RCAR_DU_MAX_LVDS               2
 
 struct rcar_du_device {
        struct device *dev;
@@ -88,6 +90,7 @@ struct rcar_du_device {
        struct rcar_du_group groups[RCAR_DU_MAX_GROUPS];
        struct platform_device *cmms[RCAR_DU_MAX_CRTCS];
        struct rcar_du_vsp vsps[RCAR_DU_MAX_VSPS];
+       struct drm_bridge *lvds[RCAR_DU_MAX_LVDS];
 
        struct {
                struct drm_property *colorkey;
diff --git a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c 
b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
index b0335da0c161..2d40da98144b 100644
--- a/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
+++ b/drivers/gpu/drm/rcar-du/rcar_du_encoder.c
@@ -91,6 +91,10 @@ int rcar_du_encoder_init(struct rcar_du_device *rcdu,
                        ret = -EPROBE_DEFER;
                        goto done;
                }
+
+               if (output == RCAR_DU_OUTPUT_LVDS0 ||
+                   output == RCAR_DU_OUTPUT_LVDS1)
+                       rcdu->lvds[output - RCAR_DU_OUTPUT_LVDS0] = bridge;
        }
 
        /*
-- 
Regards,

Laurent Pinchart

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