linux-kernel - Re: [PATCH v2 drm-dp 07/10] drm/hisilicon/hibmc: fix dp and vga cannot show together

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Message-ID: <7mgk3hueodkzodedjxpkzpf2b4x2n3fdqi42lmtsgozlaxv2tc@4cx7nb5pg7tb>
Date: Sat, 28 Jun 2025 20:06:11 +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 v2 drm-dp 07/10] drm/hisilicon/hibmc: fix dp and vga
 cannot show together

On Fri, Jun 20, 2025 at 05:31:01PM +0800, Yongbang Shi wrote:
> From: Baihan Li <libaihan@...wei.com>
> 
> If VGA and DP connected together, there will be only one can get crtc.
> Add encoder possible_clones to support two connectors enable.
> 
> Fixes: 0ab6ea261c1f ("drm/hisilicon/hibmc: add dp module in hibmc")
> 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:
> v1 -> v2:
>   - don't tie VGA and DP status, suggested by Dmitry Baryshkov.
>   - use crtc clone to let 2 connectors can display simultaneous

How does this help? I had an impression that your hw can actually
display only either to DP or to VGA. Can it send the same (aka cloned)
video stream to both connectors at the same time?

> ---
>  drivers/gpu/drm/hisilicon/hibmc/hibmc_drm_drv.c | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 

-- 
With best wishes
Dmitry