From b8bb40e071e11bfee5eba83ef112f976b1f1fa38 Mon Sep 17 00:00:00 2001
From: Bibby Hsieh <bibby.hsieh@mediatek.com>
Date: Mon, 17 Feb 2020 17:10:19 +0800
Subject: drm/mediatek: Make sure previous message done or be aborted before
Git-commit: 839cbf0531428f3f9535077a461b8631359c1165
Patch-mainline: v5.6-rc5
References: jsc#SLE-12680, jsc#SLE-12880, jsc#SLE-12882, jsc#SLE-12883, jsc#SLE-13496, jsc#SLE-15322
 send

Mediatek CMDQ driver removed atomic parameter and implementation
related to atomic. DRM driver need to make sure previous message
done or be aborted before we send next message.

If previous message is still waiting for event, it means the
setting hasn't been updated into display hardware register,
we can abort the message and send next message to update the
newest setting into display hardware.
If previous message already started, we have to wait it until
transmission has been completed.

So we flush mbox client before we send new message to controller
driver.

Signed-off-by: Bibby Hsieh <bibby.hsieh@mediatek.com>
Signed-off-by: CK Hu <ck.hu@mediatek.com>
Signed-off-by: Patrik Jakobsson <pjakobsson@suse.de>
---
 drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index debcd8e5658a..fe85e487e477 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -486,6 +486,7 @@ static void mtk_drm_crtc_hw_config(struct mtk_drm_crtc *mtk_crtc)
 	}
 #if IS_REACHABLE(CONFIG_MTK_CMDQ)
 	if (mtk_crtc->cmdq_client) {
+		mbox_flush(mtk_crtc->cmdq_client->chan, 2000);
 		cmdq_handle = cmdq_pkt_create(mtk_crtc->cmdq_client, PAGE_SIZE);
 		cmdq_pkt_clear_event(cmdq_handle, mtk_crtc->cmdq_event);
 		cmdq_pkt_wfe(cmdq_handle, mtk_crtc->cmdq_event);
-- 
2.28.0