Re: [PATCH 1/2] drm/rockchip: vop: clear DMA stop bit on flush on RK3066

From: Greg KH <gregkh@linuxfoundation.org>
To: Val Packett <val@packett.cool>
Cc: stable@vger.kernel.org, "Sandy Huang" <hjc@rock-chips.com>,
	"Heiko Stübner" <heiko@sntech.de>,
	"Andy Yan" <andy.yan@rock-chips.com>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"David Airlie" <airlied@gmail.com>,
	"Daniel Vetter" <daniel@ffwll.ch>,
	dri-devel@lists.freedesktop.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/2] drm/rockchip: vop: clear DMA stop bit on flush on RK3066
Date: Sun, 19 May 2024 09:59:47 +0200	[thread overview]
Message-ID: <2024051936-cosmetics-seismic-9fea@gregkh> (raw)
In-Reply-To: <20240519074019.10424-1-val@packett.cool>

On Sun, May 19, 2024 at 04:31:31AM -0300, Val Packett wrote:
> On the RK3066, there is a bit that must be cleared on flush, otherwise
> we do not get display output (at least for RGB).
> 
> Signed-off-by: Val Packett <val@packett.cool>
> Cc: stable@vger.kernel.org
> ---
> Hi! This was required to get display working on an old RK3066 tablet,
> along with the next tiny patch in the series enabling the RGB output.
> 
> I have spent quite a lot of time banging my head against the wall debugging
> that display (especially since at the same time a scaler chip is used for
> LVDS encoding), but finally adding debug prints showed that RK3066_SYS_CTRL0
> ended up being reset to all-zero after being written correctly upon init.
> Looking at the register definitions in the vendor driver revealed that the
> reason was pretty self-explanatory: "dma_stop".

What commit id does this fix?

thanks,

greg k-h

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