linux-kernel - [PATCH v3 drm-dp 09/11] drm/hisilicon/hibmc: fix no showing problem with loading hibmc manually

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Message-ID: <20250718065125.2892404-10-shiyongbang@huawei.com>
Date: Fri, 18 Jul 2025 14:51:23 +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>,
	<jani.nikula@...ux.intel.com>, <dri-devel@...ts.freedesktop.org>,
	<linux-kernel@...r.kernel.org>
Subject: [PATCH v3 drm-dp 09/11] 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().

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>
---
ChangeLog:
v2 -> v3:
  - fix the issue commit ID, suggested by Dmitry Baryshkov.
---
 drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
index 7fbd51ffd778..36daf7542d40 100644
--- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
+++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
@@ -181,6 +181,8 @@ int hibmc_dp_hw_init(struct hibmc_dp *dp)
 	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);
 	writel(HIBMC_DP_DPTX_RST, dp_dev->base + HIBMC_DP_DPTX_RST_CTRL);
 	/* clock enable */
 	writel(HIBMC_DP_CLK_EN, dp_dev->base + HIBMC_DP_DPTX_CLK_CTRL);
-- 
2.33.0