linux-kernel - Re: [PATCH drm-dp 10/10] drm/hisilicon/hibmc: fix no showing problem with loading hibmc manually

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <czs4ingsrnuaqlbn3f7ko65pzhydcuuiglyh5ksrpfcz5zur74@vzgzyjkcae63>
Date: Sun, 8 Jun 2025 15:54:05 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@....qualcomm.com>
To: Yongbang Shi <shiyongbang@...wei.com>
Cc: 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, liangjian010@...wei.com,
        chenjianmin@...wei.com, lidongming5@...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: Re: [PATCH drm-dp 10/10] drm/hisilicon/hibmc: fix no showing problem
 with loading hibmc manually

On Fri, May 30, 2025 at 05:54:32PM +0800, Yongbang Shi wrote:
> 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: 94ee73ee3020 ("drm/hisilicon/hibmc: add dp hw moduel in hibmc driver")

Technically... yes and no. The function was written this way in that
commit, however HPD signals were not handled until the latter commit.

> Signed-off-by: Baihan Li <libaihan@...wei.com>
> ---
>  drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c | 6 ++++--
>  1 file changed, 4 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 4f93d60b932b..e1b9589ce639 100644
> --- a/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
> +++ b/drivers/gpu/drm/hisilicon/hibmc/dp/dp_hw.c
> @@ -172,13 +172,15 @@ 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);
>  	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);

There are two independent changes here. Split them into two commits.

>  	/* clock enable */
>  	writel(HIBMC_DP_CLK_EN, dp_dev->base + HIBMC_DP_DPTX_CLK_CTRL);
>  
> -- 
> 2.33.0
> 

-- 
With best wishes
Dmitry