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From: Hsiao Chien Sung <shawn.sung@mediatek.com>
To: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>,
	Chun-Kuang Hu <chunkuang.hu@kernel.org>
CC: Philipp Zabel <p.zabel@pengutronix.de>, David Airlie <airlied@gmail.com>,
	Daniel Vetter <daniel@ffwll.ch>, Matthias Brugger <matthias.bgg@gmail.com>,
	Bibby Hsieh <bibby.hsieh@mediatek.com>, CK Hu <ck.hu@mediatek.com>, Sean Paul
	<seanpaul@chromium.org>, Fei Shao <fshao@chromium.org>, Jason Chen
	<jason-ch.chen@mediatek.corp-partner.google.com>, "Nancy . Lin"
	<nancy.lin@mediatek.com>, <dri-devel@lists.freedesktop.org>,
	<linux-mediatek@lists.infradead.org>, <linux-arm-kernel@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>, Hsiao Chien Sung <shawn.sung@mediatek.com>
Subject: [PATCH v5 06/13] drm/mediatek: Turn off the layers with zero width or height
Date: Thu, 15 Feb 2024 18:11:12 +0800
Message-ID: <20240215101119.12629-7-shawn.sung@mediatek.com>
In-Reply-To: <20240215101119.12629-1-shawn.sung@mediatek.com>
References: <20240215101119.12629-1-shawn.sung@mediatek.com>
Precedence: bulk
MIME-Version: 1.0
Content-Type: text/plain

We found that IGT (Intel GPU Tool) will try to commit layers with
zero width or height and lead to undefined behaviors in hardware.
Disable the layers in such a situation.

Fixes: 777b7bc86a0a3 ("drm/mediatek: Add ovl_adaptor support for MT8195")
Fixes: fa97fe71f6f93 ("drm/mediatek: Add ETHDR support for MT8195")

Signed-off-by: Hsiao Chien Sung <shawn.sung@mediatek.com>
---
 drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c | 2 +-
 drivers/gpu/drm/mediatek/mtk_ethdr.c            | 7 ++++++-
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
index d4a13a1402148..68a20312ac6f1 100644
--- a/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
+++ b/drivers/gpu/drm/mediatek/mtk_disp_ovl_adaptor.c
@@ -157,7 +157,7 @@ void mtk_ovl_adaptor_layer_config(struct device *dev, unsigned int idx,
 	merge = ovl_adaptor->ovl_adaptor_comp[OVL_ADAPTOR_MERGE0 + idx];
 	ethdr = ovl_adaptor->ovl_adaptor_comp[OVL_ADAPTOR_ETHDR0];
 
-	if (!pending->enable) {
+	if (!pending->enable || !pending->width || !pending->height) {
 		mtk_merge_stop_cmdq(merge, cmdq_pkt);
 		mtk_mdp_rdma_stop(rdma_l, cmdq_pkt);
 		mtk_mdp_rdma_stop(rdma_r, cmdq_pkt);
diff --git a/drivers/gpu/drm/mediatek/mtk_ethdr.c b/drivers/gpu/drm/mediatek/mtk_ethdr.c
index 73dc4da3ba3bd..69872b77922eb 100644
--- a/drivers/gpu/drm/mediatek/mtk_ethdr.c
+++ b/drivers/gpu/drm/mediatek/mtk_ethdr.c
@@ -160,7 +160,12 @@ void mtk_ethdr_layer_config(struct device *dev, unsigned int idx,
 	if (idx >= 4)
 		return;
 
-	if (!pending->enable) {
+	if (!pending->enable || !pending->width || !pending->height) {
+		/*
+		 * instead of disabling layer with MIX_SRC_CON directly
+		 * set the size to 0 to avoid screen shift due to mixer
+		 * mode switch (hardware behavior)
+		 */
 		mtk_ddp_write(cmdq_pkt, 0, &mixer->cmdq_base, mixer->regs, MIX_L_SRC_SIZE(idx));
 		return;
 	}
-- 
2.18.0