From: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: catalin.marinas@arm.com, will.deacon@arm.com,
leif.lindholm@linaro.org, linux-acpi@vger.kernel.org,
lee.jones@linaro.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [RFC PATCH] acpi/arm64: ignore 5.1 FADTs that are reported as 5.0
Date: Thu, 20 Jun 2019 10:43:57 +0100 [thread overview]
Message-ID: <20190620094357.GA20872@e121166-lin.cambridge.arm.com> (raw)
In-Reply-To: <20190619121831.7614-1-ard.biesheuvel@linaro.org>
On Wed, Jun 19, 2019 at 02:18:31PM +0200, Ard Biesheuvel wrote:
> Some Qualcomm Snapdragon based laptops built to run Microsoft Windows
> are clearly ACPI 5.1 based, given that that is the first ACPI revision
> that supports ARM, and introduced the FADT 'arm_boot_flags' field,
> which has a non-zero field on those systems.
>
> So in these cases, infer from the ARM boot flags that the FADT must be
> 5.1 or later, and treat it as 5.1.
>
> Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> ---
> arch/arm64/kernel/acpi.c | 10 +++++++---
> 1 file changed, 7 insertions(+), 3 deletions(-)
AFAICS this should be harmless, so:
Acked-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
> index 803f0494dd3e..7722e85fb69c 100644
> --- a/arch/arm64/kernel/acpi.c
> +++ b/arch/arm64/kernel/acpi.c
> @@ -155,10 +155,14 @@ static int __init acpi_fadt_sanity_check(void)
> */
> if (table->revision < 5 ||
> (table->revision == 5 && fadt->minor_revision < 1)) {
> - pr_err("Unsupported FADT revision %d.%d, should be 5.1+\n",
> + pr_err(FW_BUG "Unsupported FADT revision %d.%d, should be 5.1+\n",
> table->revision, fadt->minor_revision);
> - ret = -EINVAL;
> - goto out;
> +
> + if (!fadt->arm_boot_flags) {
> + ret = -EINVAL;
> + goto out;
> + }
> + pr_err("FADT has ARM boot flags set, assuming 5.1\n");
> }
>
> if (!(fadt->flags & ACPI_FADT_HW_REDUCED)) {
> --
> 2.20.1
>
_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2019-06-20 9:44 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-19 12:18 [RFC PATCH] acpi/arm64: ignore 5.1 FADTs that are reported as 5.0 Ard Biesheuvel
2019-06-19 12:24 ` Sudeep Holla
2019-06-20 7:57 ` Lee Jones
2019-06-20 9:49 ` Lorenzo Pieralisi
2019-06-20 12:25 ` Lee Jones
2019-06-19 12:26 ` Lee Jones
2019-06-20 7:53 ` Graeme Gregory
2019-06-20 9:43 ` Lorenzo Pieralisi [this message]
2019-06-24 6:39 ` Hanjun Guo
2019-06-24 14:55 ` Catalin Marinas
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20190620094357.GA20872@e121166-lin.cambridge.arm.com \
--to=lorenzo.pieralisi@arm.com \
--cc=ard.biesheuvel@linaro.org \
--cc=catalin.marinas@arm.com \
--cc=lee.jones@linaro.org \
--cc=leif.lindholm@linaro.org \
--cc=linux-acpi@vger.kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=will.deacon@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).