Devicetree
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From: Krzysztof Kozlowski <krzk@kernel.org>
To: "Michał Kopeć" <michal@nozomi.space>
Cc: "Boris Brezillon" <boris.brezillon@collabora.com>,
	"Steven Price" <steven.price@arm.com>,
	"Adrián Larumbe" <adrian.larumbe@collabora.com>,
	"Rob Herring" <robh@kernel.org>,
	"Krzysztof Kozlowski" <krzk+dt@kernel.org>,
	"Conor Dooley" <conor+dt@kernel.org>,
	"Matthias Brugger" <matthias.bgg@gmail.com>,
	"AngeloGioacchino Del Regno"
	<angelogioacchino.delregno@collabora.com>,
	dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org,
	linux-mediatek@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/3] dt-bindings: gpu: mali-bifrost: Add the MT8188 MFGCFG phandle
Date: Fri, 9 Oct 2026 09:01:31 +0200	[thread overview]
Message-ID: <20261009-sparkling-broad-dormouse-ae1ff8@quoll> (raw)
In-Reply-To: <20261003200132.866240-2-michal@nozomi.space>

On Sat, Oct 03, 2026 at 10:01:30PM +0200, Michał Kopeć wrote:
> On MT8188 the GPU timestamp counter only counts once a register in the
> MFG configuration block routes the SoC system timer to it, and the
> setting is lost whenever the GPU power domain is turned off. The GPU
> driver has to restore it on every power-up, so it needs a reference to
> that block.

This looks rather like power domain issue, e.g. missing restore of
registers. Otherwise next time there will be one more phandle and then
one more, each for one register being lost during power down.

> 
> Add an optional mediatek,mfgcfg phandle. Allow it on MT8370 as well,
> which shares the GPU and the MFG block with MT8188 and its GPU node in
> mt8188.dtsi. It is optional so that existing devicetrees stay valid;
> without it the timestamp counter reads zero, as before.
> 
> Signed-off-by: Michał Kopeć <michal@nozomi.space>
> ---
>  .../bindings/gpu/arm,mali-bifrost.yaml          | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)

Best regards,
Krzysztof


  reply	other threads:[~2026-10-09  7:01 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-10-03 20:01 [PATCH 0/3] drm/panfrost: Enable the GPU timestamp counter on MT8188 Michał Kopeć
2026-10-03 20:01 ` [PATCH 1/3] dt-bindings: gpu: mali-bifrost: Add the MT8188 MFGCFG phandle Michał Kopeć
2026-10-09  7:01   ` Krzysztof Kozlowski [this message]
2026-10-03 20:01 ` [PATCH 2/3] drm/panfrost: Enable the GPU timestamp counter on MT8188 Michał Kopeć
2026-10-03 20:10   ` sashiko-bot
2026-10-03 20:01 ` [PATCH 3/3] arm64: dts: mediatek: mt8188: Add the MFGCFG phandle to the GPU Michał Kopeć
2026-10-03 20:12   ` sashiko-bot

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