Re: [PATCH 2/9] drm/rockchip: vop2: Reset AXI and DCLK to improve robustness

From: "Diederik de Haas" <diederik@cknow-tech.com>
To: "Cristian Ciocaltea" <cristian.ciocaltea@collabora.com>,
	"Diederik de Haas" <diederik@cknow-tech.com>,
	"Sandy Huang" <hjc@rock-chips.com>,
	"Heiko Stübner" <heiko@sntech.de>,
	"Andy Yan" <andy.yan@rock-chips.com>,
	"David Airlie" <airlied@gmail.com>,
	"Simona Vetter" <simona@ffwll.ch>,
	"Maarten Lankhorst" <maarten.lankhorst@linux.intel.com>,
	"Maxime Ripard" <mripard@kernel.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Philipp Zabel" <p.zabel@pengutronix.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>,
	"Luca Ceresoli" <luca.ceresoli@bootlin.com>
Cc: <kernel@collabora.com>, "Andy Yan" <andyshrk@163.com>,
	<dri-devel@lists.freedesktop.org>, <devicetree@vger.kernel.org>,
	<linux-arm-kernel@lists.infradead.org>,
	<linux-rockchip@lists.infradead.org>,
	<linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/9] drm/rockchip: vop2: Reset AXI and DCLK to improve robustness
Date: Mon, 06 Jul 2026 00:20:13 +0200	[thread overview]
Message-ID: <DJQZJUFLM425.2J87266L7CGT8@cknow-tech.com> (raw)
In-Reply-To: <c8242f5c-ec74-489e-b378-f225ec3a0135@collabora.com>

Hi Cristian,

On Sun Jul 5, 2026 at 10:46 PM CEST, Cristian Ciocaltea wrote:
> On 7/5/26 4:28 PM, Diederik de Haas wrote:
>> On Wed Jun 17, 2026 at 8:52 PM CEST, Cristian Ciocaltea wrote:
>>> Assert the AXI reset in the CRTC disable path, and the VP DCLK reset in
>>> the enable path.
>>>
>>> These resets are intended to leave the hardware in a clean state for the
>>> next use, helping recover from exceptions such as IOMMU page faults, as
>>> well as to prevent random display output glitches, such as a blank
>>> image, observed when switching modes that also change the color format,
>>> e.g. from RGB to YUV420 and vice versa.
>>>
>>> For now this seems to affect only the RK3588, hence the resets are
>>> optional and will be provided in the device tree for this SoC only.
>> 
>> Why do you think it only effect RK3588? 
>
> My findings are exclusively in the context of validating YUV support for DW HDMI
> QP, hence targeting RK3588 and RK3576.  Since RK3576 didn't exhibit any
> anomalies, I concluded the resets are needed just for RK3588.

Ok, that's indeed a different technology stack.

>> I reported about my RK3568 test here:
>> https://lore.kernel.org/linux-rockchip/DFRU6ODDM71P.3NQGLRK8IVDUY@cknow-tech.com/
>> "I then went on to try LibreELEC's builds. The artifacts I (sometimes)
>> saw, were gone :-D OTOH, I did get several major issues 'in return',
>> like rk_iommu Page fault resulting in a black screen and the only way to
>> 'recover' from it, was a reboot."
>> 
>> And I reported some more test results here:
>> https://forum.libreelec.tv/thread/29953-le13-testing-for-rk3288-rk3328-rk3399-rk3566-rk3568-rk3576-rk3588/?postID=204691#post204691
>> 
>> That seems to me a (strong) indication it also affects RK3566/RK3568?
>
> If coincidentally this helps improve the reliability of some of the older SoCs
> as well, the resets can easily be added to the corresponding DTs and submitted
> as a follow-up series.

Agreed. Thanks :)

Cheers,
  Diederik

_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip