Re: [RFC PATCH 3/8] drm: verisilicon: add a driver for Verisilicon display controllers

From: Drew Fustini <fustini@kernel.org>
To: Icenowy Zheng <uwu@icenowy.me>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	Maxime Ripard <mripard@kernel.org>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	David Airlie <airlied@gmail.com>, Simona Vetter <simona@ffwll.ch>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>, Guo Ren <guoren@kernel.org>,
	Fu Wei <wefu@redhat.com>, Philipp Zabel <p.zabel@pengutronix.de>,
	Heiko Stuebner <heiko@sntech.de>,
	Andrzej Hajda <andrzej.hajda@intel.com>,
	Neil Armstrong <neil.armstrong@linaro.org>,
	Robert Foss <rfoss@kernel.org>,
	Laurent Pinchart <Laurent.pinchart@ideasonboard.com>,
	Jonas Karlman <jonas@kwiboo.se>,
	Jernej Skrabec <jernej.skrabec@gmail.com>,
	Michal Wilczynski <m.wilczynski@samsung.com>,
	Han Gao <rabenda.cn@gmail.com>, Yao Zi <ziyao@disroot.org>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org
Subject: Re: [RFC PATCH 3/8] drm: verisilicon: add a driver for Verisilicon display controllers
Date: Sun, 17 Aug 2025 11:39:52 -0700	[thread overview]
Message-ID: <aKIh+MLEO2aM/vO7@x1> (raw)
In-Reply-To: <20250814164048.2336043-4-uwu@icenowy.me>

On Fri, Aug 15, 2025 at 12:40:43AM +0800, Icenowy Zheng wrote:
> This is a from-scratch driver targeting Verisilicon DC-series display
> controllers, which feature self-identification functionality like their
> GC-series GPUs.
> 
> Only DC8200 is being supported now, and only the main framebuffer is set
> up (as the DRM primary plane). Support for more DC models and more
> features is my further targets.
> 
> As the display controller is delivered to SoC vendors as a whole part,
> this driver does not use component framework and extra bridges inside a
> SoC is expected to be implemented as dedicated bridges (this driver
> properly supports bridge chaining).
> 
> Signed-off-by: Icenowy Zheng <uwu@icenowy.me>

Thanks for working on this!

[snip]
> diff --git a/drivers/gpu/drm/verisilicon/vs_primary_plane.c b/drivers/gpu/drm/verisilicon/vs_primary_plane.c
> new file mode 100644
> index 0000000000000..25d6e01cc8b71
> --- /dev/null
> +++ b/drivers/gpu/drm/verisilicon/vs_primary_plane.c
[snip]
> +static void vs_primary_plane_atomic_update(struct drm_plane *plane,
> +					   struct drm_atomic_state *atomic_state)
> +{
> +	struct drm_plane_state *state = drm_atomic_get_new_plane_state(atomic_state,
> +								       plane);
> +	struct drm_framebuffer *fb = state->fb;
> +	struct drm_crtc *crtc = state->crtc;
> +	struct drm_gem_dma_object *gem;
> +	struct vs_dc *dc;
> +	struct vs_crtc *vcrtc;
> +	struct vs_format fmt;
> +	unsigned int output, bpp;
> +	dma_addr_t dma_addr;
> +
> +	if (!crtc)
> +		return;
> +
> +	DRM_DEBUG_DRIVER("Updating output %d primary plane\n", output);

clang flagged this when building. I think this needs to be after the
line below that assigns vcrtc->id to output.

> +
> +	vcrtc = drm_crtc_to_vs_crtc(crtc);
> +	output = vcrtc->id;

Thanks,
Drew

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