linux-kernel - Re: [PATCH v3] pmdomain: imx: gpcv2: Fix the imx8mm gpu hang due to wrong adb400 reset

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Message-ID: <CAOMZO5Ag6jtVqeXW30QNy5+1ykmGTt4G8DxcsyOUMvNaeJf5Ug@mail.gmail.com>
Date: Sat, 24 Jan 2026 18:20:42 -0300
From: Fabio Estevam <festevam@...il.com>
To: Jacky Bai <ping.bai@....com>
Cc: Ulf Hansson <ulf.hansson@...aro.org>, Shawn Guo <shawnguo@...nel.org>, 
	Sascha Hauer <s.hauer@...gutronix.de>, Lucas Stach <l.stach@...gutronix.de>, 
	Pengutronix Kernel Team <kernel@...gutronix.de>, Rob Herring <robh@...nel.org>, 
	Krzysztof Kozlowski <krzk+dt@...nel.org>, Conor Dooley <conor+dt@...nel.org>, linux-pm@...r.kernel.org, 
	imx@...ts.linux.dev, linux-arm-kernel@...ts.infradead.org, 
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org
Subject: Re: [PATCH v3] pmdomain: imx: gpcv2: Fix the imx8mm gpu hang due to
 wrong adb400 reset

On Thu, Jan 22, 2026 at 11:51 PM Jacky Bai <ping.bai@....com> wrote:
>
> On i.MX8MM, the GPUMIX, GPU2D, and GPU3D blocks share a common reset
> domain. Due to this hardware limitation, powering off/on GPU2D or GPU3D
> also triggers a reset of the GPUMIX domain, including its ADB400 port.
> However, the ADB400 interface must always be placed into power‑down mode
> before being reset.
>
> Currently the GPUMIX and GPU2D/3D power domains rely on runtime PM to
> handle dependency ordering. In some corner cases, the GPUMIX power off
> sequence is skipped, leaving the ADB400 port active when GPU2D/3D reset.
> This causes the GPUMIX ADB400 port to be reset while still active,
> leading to unpredictable bus behavior and GPU hangs.
>
> To avoid this, refine the power‑domain control logic so that the GPUMIX
> ADB400 port is explicitly powered down and powered up as part of the GPU
> power domain on/off sequence. This ensures proper ordering and prevents
> incorrect ADB400 reset.
>
> Suggested-by: Lucas Stach <l.stach@...gutronix.de>
> Signed-off-by: Jacky Bai <ping.bai@....com>

Shouldn't this have a Fixes tag?