linux-kernel - [REGRESSION] [BISECTED] drm/sun4i: hdmi: No HDMI output with BananaPI M1 on 6.9

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Message-ID: <aCJZmm8rC0RwbcBX@a98shuttle.de>
Date: Mon, 12 May 2025 22:27:06 +0200
From: Michael <michael@...sekall.de>
To: Maxime Ripard <mripard@...nel.org>, Chen-Yu Tsai <wens@...e.org>,
	Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
	Thomas Zimmermann <tzimmermann@...e.de>,
	David Airlie <airlied@...il.com>, Daniel Vetter <daniel@...ll.ch>,
	Jernej Skrabec <jernej.skrabec@...il.com>,
	Samuel Holland <samuel@...lland.org>
Cc: dri-devel@...ts.freedesktop.org, linux-arm-kernel@...ts.infradead.org,
	linux-sunxi@...ts.linux.dev, linux-kernel@...r.kernel.org,
	regressions@...ts.linux.dev
Subject: [REGRESSION] [BISECTED] drm/sun4i: hdmi: No HDMI output with
 BananaPI M1 on 6.9

Hi,

with v6.9 and later there is no output on the BananaPI HDMI connector.

I have bisected the issue to the following commit:

   358e76fd613a ("drm/sun4i: hdmi: Consolidate atomic_check and mode_valid")

With this patch, sun4i_hdmi_connector_clock_valid() is occasionally 
called with clock=0, causing the function to return MODE_NOCLOCK.
In the old sun4i_hdmi_mode_valid() before the patch, mode->clock is 
always!=0, maybe that gives someone a hint.

-- 
Michael