From: Catalin Marinas <catalin.marinas@arm.com>
To: Yassine Oudjana <y.oudjana@protonmail.com>
Cc: "will@kernel.org" <will@kernel.org>,
"ardb@kernel.org" <ardb@kernel.org>,
"arnd@arndb.de" <arnd@arndb.de>,
"kernel-team@android.com" <kernel-team@android.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"mark.rutland@arm.com" <mark.rutland@arm.com>,
"vincent.whitchurch@axis.com" <vincent.whitchurch@axis.com>,
"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH] arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES)
Date: Tue, 6 Jul 2021 11:26:35 +0100 [thread overview]
Message-ID: <20210706102634.GB24903@arm.com> (raw)
In-Reply-To: <uHgsRacR8hJ7nW-I-pIcehzg-lNIn7NJvaL7bP9tfAftFsBjsgaY2qTjG9zyBgxHkjNL1WPNrD7YVv2JVD2_Wy-a5VTbcq-1xEi8ZnwrXBo=@protonmail.com>
On Tue, Jul 06, 2021 at 09:26:59AM +0000, Yassine Oudjana wrote:
> In-Reply-To: <20210527124356.22367-1-will@kernel.org>
> > Reduce ARCH_DMA_MINALIGN to 64 bytes and allow the warning/taint to
> > indicate if there are machines that unknowingly rely on this.
>
> The warning is being triggered on Qualcomm MSM8996, as well as the out-of-spec taint:
Is this booting with ACPI or DT?
> ------------[ cut here ]------------
> rtc-pm8xxx 400f000.qcom,spmi:pmic@0:rtc@6000: ARCH_DMA_MINALIGN smaller than CTR_EL0.CWG (64 < 128)
> WARNING: CPU: 0 PID: 1 at arch/arm64/mm/dma-mapping.c:45 arch_setup_dma_ops+0xf8/0x10c
[...]
> This warning is triggered with nearly every driver probe, not only rtc-pm8xxx.
I have a suspicion none of the reported devices actually do any DMA, so
in practice it should be safe but we need to figure out why
arch_setup_dma_ops() gets called.
--
Catalin
next prev parent reply other threads:[~2021-07-06 10:26 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20210527124356.22367-1-will@kernel.org>
2021-07-06 9:26 ` [PATCH] arm64: cache: Lower ARCH_DMA_MINALIGN to 64 (L1_CACHE_BYTES) Yassine Oudjana
2021-07-06 10:26 ` Catalin Marinas [this message]
2021-07-06 13:29 ` Robin Murphy
2021-07-06 13:33 ` Will Deacon
2021-07-06 13:44 ` Marc Zyngier
2021-07-06 14:21 ` Robin Murphy
2021-07-06 14:30 ` Arnd Bergmann
2021-07-06 14:46 ` Marc Zyngier
2021-07-06 15:43 ` Arnd Bergmann
2021-07-06 17:15 ` Yassine Oudjana
2021-07-06 20:33 ` Arnd Bergmann
2021-07-06 22:27 ` Bjorn Andersson
2021-07-07 9:27 ` Will Deacon
2021-07-07 8:24 ` Yassine Oudjana
2021-07-07 9:29 ` Arnd Bergmann
2021-07-07 14:41 ` Jeffrey Hugo
2021-07-08 20:59 ` Jeffrey Hugo
2021-07-09 8:48 ` Will Deacon
2021-07-09 17:10 ` Catalin Marinas
2021-07-06 16:20 ` Will Deacon
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