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From:   Pi-Hsun Shih <pihsun@chromium.org>
Cc:     Pi-Hsun Shih <pihsun@chromium.org>,
        Yongqiang Niu <yongqiang.niu@mediatek.com>,
        CK Hu <ck.hu@mediatek.com>,
        Philipp Zabel <p.zabel@pengutronix.de>,
        David Airlie <airlied@linux.ie>,
        Daniel Vetter <daniel@ffwll.ch>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        Sean Paul <seanpaul@chromium.org>,
        dri-devel@lists.freedesktop.org (open list:DRM DRIVERS FOR MEDIATEK),
        linux-arm-kernel@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support),
        linux-mediatek@lists.infradead.org (moderated list:ARM/Mediatek SoC
        support), linux-kernel@vger.kernel.org (open list)
Subject: [PATCH] drm/mediatek: Fix can't get component for external display plane.
Date:   Wed, 27 Nov 2019 18:04:19 +0800
Message-Id: <20191127100419.130300-1-pihsun@chromium.org>
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From: Yongqiang Niu <yongqiang.niu@mediatek.com>

The original logic is ok for primary display, but will not find out
component for external display.

For example, plane->index is 6 for external display, but there are only
2 layer nr in external display, and this condition will never happen:
if (plane->index < (count + mtk_ddp_comp_layer_nr(comp)))

Fix this by using the offset of the plane to mtk_crtc->planes as index,
instead of plane->index.

Fixes: d6b53f68356f ("drm/mediatek: Add helper to get component for a plane")
Signed-off-by: Yongqiang Niu <yongqiang.niu@mediatek.com>
Signed-off-by: Pi-Hsun Shih <pihsun@chromium.org>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index f80a8ba75977..b34e7d70702a 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -215,11 +215,12 @@ struct mtk_ddp_comp *mtk_drm_ddp_comp_for_plane(struct drm_crtc *crtc,
 	struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
 	struct mtk_ddp_comp *comp;
 	int i, count = 0;
+	unsigned int local_index = plane - mtk_crtc->planes;
 
 	for (i = 0; i < mtk_crtc->ddp_comp_nr; i++) {
 		comp = mtk_crtc->ddp_comp[i];
-		if (plane->index < (count + mtk_ddp_comp_layer_nr(comp))) {
-			*local_layer = plane->index - count;
+		if (local_index < (count + mtk_ddp_comp_layer_nr(comp))) {
+			*local_layer = local_index - count;
 			return comp;
 		}
 		count += mtk_ddp_comp_layer_nr(comp);

base-commit: 1875ff320f14afe21731a6e4c7b46dd33e45dfaa
-- 
2.24.0.393.g34dc348eaf-goog