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From: Alyssa Rosenzweig <alyssa@collabora.com>
To: Robin Murphy <robin.murphy@arm.com>
Cc: Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
	linux-mediatek@lists.infradead.org,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Ikjoon Jang <ikjn@chromium.org>,
	Chun-Jie Chen <chun-jie.chen@mediatek.com>,
	Weiyi Lu <weiyi.lu@mediatek.com>,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	Nick Fan <Nick.Fan@mediatek.com>,
	Nicolas Boichat <drinkcat@chromium.org>
Subject: Re: [PATCH] clk: mediatek: Disable ACP to fix 3D on MT8192
Date: Fri, 14 Jan 2022 08:47:45 -0500	[thread overview]
Message-ID: <YeF/AYZ0DuKGwLLk@maud> (raw)
In-Reply-To: <eb6d11af-ff48-a366-d428-77bcaa250a8a@arm.com>

> > That links to an internal Google issue tracker which I assume has more
> > information on the bug. I would appreciate if someone from Google or
> > MediaTek could explain what this change actually does and why it's
> > necessary on MT8192.
> > 
> > At any rate, this register logically belongs to the MT8192 "infra" clock
> > device, so it makes sense to set it there too. This avoids adding any
> > platform-specific hacks to the 3D driver, either mainline (Panfrost) or
> > legacy (kbase).
> 
> Does this really have anything to do with clocks?

I have no idea. MediaTek, Google, please explain.

> In particular, "ACP" usually refers to the Accelerator Coherency Port
> of a CPU cluster or DSU, and given the stated symptom of the issue
> affected by it, my first guess would be that this bit might indeed
> control routing of GPU traffic either to the ACP or the (presumably
> non-coherent) main interconnect.

I'd easily believe that.

> If that is the case, I think this would logically belong as a SoC-specific
> quirk in panfrost, where we'd need to retrieve the syscon regmap for
> ourselves (see around line 800 of drivers/iommu/mtk_iommu.c for a similar
> example).

Alright. Doing this in panfrost seems ugly but if that's the right place
for it, that's the right place for it.

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  reply	other threads:[~2022-01-14 13:49 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-10 18:13 [PATCH] clk: mediatek: Disable ACP to fix 3D on MT8192 Alyssa Rosenzweig
2022-01-14  2:08 ` Stephen Boyd
2022-01-14 13:23 ` Robin Murphy
2022-01-14 13:47   ` Alyssa Rosenzweig [this message]
2022-01-18  7:19     ` Chen-Yu Tsai
2022-01-18 15:01       ` Robin Murphy
2022-01-19  2:18         ` Stephen Boyd
2022-01-20 14:22           ` Robin Murphy
2022-01-20 14:27             ` Alyssa Rosenzweig
2022-02-15 10:44               ` AngeloGioacchino Del Regno
2022-02-15 15:21                 ` Robin Murphy
2022-02-15 16:12                   ` AngeloGioacchino Del Regno
2022-02-17 21:40                   ` Stephen Boyd
2022-01-14 22:55   ` Stephen Boyd

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