linux-kernel - [PATCH v5 drm-dp 3/4] drm/hisilicon/hibmc: fix no showing problem with loading hibmc manually

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Message-ID: <20250826021744.3237574-4-shiyongbang@huawei.com>
Date: Tue, 26 Aug 2025 10:17:43 +0800
From: Yongbang Shi <shiyongbang@...wei.com>
To: <xinliang.liu@...aro.org>, <tiantao6@...ilicon.com>,
	<maarten.lankhorst@...ux.intel.com>, <mripard@...nel.org>,
	<tzimmermann@...e.de>, <airlied@...il.com>, <daniel@...ll.ch>,
	<kong.kongxinwei@...ilicon.com>, <dmitry.baryshkov@....qualcomm.com>
CC: <liangjian010@...wei.com>, <chenjianmin@...wei.com>,
	<fengsheng5@...wei.com>, <shiyongbang@...wei.com>, <libaihan@...wei.com>,
	<shenjian15@...wei.com>, <shaojijie@...wei.com>,
	<dri-devel@...ts.freedesktop.org>, <linux-kernel@...r.kernel.org>
Subject: [PATCH v5 drm-dp 3/4] drm/hisilicon/hibmc: fix no showing problem with loading hibmc manually

From: Baihan Li <libaihan@...wei.com>

When using command rmmod and insmod, there is no showing in second time
insmoding. Because DP controller won't send HPD signals, if connection
doesn't change or controller isn't reset. So add reset before unreset
in hibmc_dp_hw_init().

And also need to move the HDCP cfg after DP controller de-resets, so
that HDCP configuration takes effect.

Fixes: 3c7623fb5bb6 ("drm/hisilicon/hibmc: Enable this hot plug detect of irq feature")
Signed-off-by: Baihan Li <libaihan@...wei.com>
Signed-off-by: Yongbang Shi <shiyongbang@...wei.com>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
---
ChangeLog:
v4 -> v5:
  - combined 9 and 11 patch together, suggested by Dmitry Baryshkov.
---
 drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
index f8e1b437c385..25a06da05030 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
@@ -176,13 +176,16 @@ int hibmc_dp_hw_init(struct hibmc_dp *dp)
 	dp_dev->link.cap.lanes = 0x2;
 	dp_dev->link.cap.link_rate = DP_LINK_BW_8_1;
 
-	/* hdcp data */
-	writel(HIBMC_DP_HDCP, dp_dev->base + HIBMC_DP_HDCP_CFG);
 	/* int init */
 	writel(0, dp_dev->base + HIBMC_DP_INTR_ENABLE);
 	writel(HIBMC_DP_INT_RST, dp_dev->base + HIBMC_DP_INTR_ORIGINAL_STATUS);
 	/* rst */
+	writel(0, dp_dev->base + HIBMC_DP_DPTX_RST_CTRL);
+	usleep_range(30, 50);
+	/* de-rst */
 	writel(HIBMC_DP_DPTX_RST, dp_dev->base + HIBMC_DP_DPTX_RST_CTRL);
+	/* hdcp data */
+	writel(HIBMC_DP_HDCP, dp_dev->base + HIBMC_DP_HDCP_CFG);
 	/* clock enable */
 	writel(HIBMC_DP_CLK_EN, dp_dev->base + HIBMC_DP_DPTX_CLK_CTRL);
 
-- 
2.33.0