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Subject: Re: New warning: PRMT not present (was: not found)
To:     Aubrey Li <aubrey.li@linux.intel.com>,
        "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
        Len Brown <lenb@kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        LKML <linux-kernel@vger.kernel.org>
References: <64150c95-3f7d-d21f-d6fb-b9d478ed6798@molgen.mpg.de>
 <766862fc-80fa-775b-6e63-6d9422d1d258@molgen.mpg.de>
 <CAJZ5v0i91+kPe4C-wy+oCDvYbR_Vp=MzwEyL+8T3xJU5O4XjRA@mail.gmail.com>
 <c6aaf684-2cd1-f615-34e1-7ef2020ae2d2@molgen.mpg.de>
 <54b6f8cb-4714-587c-b2d0-98134473293d@linux.intel.com>
From:   Paul Menzel <pmenzel@molgen.mpg.de>
Message-ID: <a55ebebc-c8f8-5654-adff-3569d1de2e27@molgen.mpg.de>
Date:   Tue, 7 Sep 2021 09:22:33 +0200
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Dear Aubrey,


Thank you very much for quick reply.


Am 07.09.21 um 05:26 schrieb Aubrey Li:

> On 9/6/21 10:15 PM, Paul Menzel wrote:

>> Am 06.09.21 um 14:02 schrieb Rafael J. Wysocki:
>>>
>>> This should be addressed by commit 2bbfa0addd63 "ACPI: PRM: Deal with
>>> table not present or no module found", or yet another fix is needed.
>>
>> Linux still warns on my systems with Linux 5.14 and Linus’ master in QEMU i440fx and an Asus F2A85-M PRO.
> 
> Does the following patch address your problem?

Yes, it does. With this patch cherry-picked to my Linux tree, the 
warning is gone in QEMU.

     qemu-system-x86_64 -kernel /dev/shm/bzImage -append 
"earlyprintk=serial,ttyS0,keep console=ttyS0,115200 console=tty0" 
-display none -serial stdio

(I have to check my configuration, why normal serial console does not 
work in QEMU.)

> ----------------------------------------------------------------------
>  From 52fda76410fcb7a3661687e960634d34fa44fb5f Mon Sep 17 00:00:00 2001
> From: Aubrey Li <aubrey.li@intel.com>
> Date: Tue, 7 Sep 2021 11:06:59 +0800
> Subject: [PATCH] ACPI/RPM: Find PRMT table before parse it

What does RPM mean?

> Find and verify PRMT table before parse it, this eliminates a
> warning on machines without PRMT table.

Please paste the warning for people grepping the commit messages.

     ACPI: PRMT not present

> Signed-off-by: Aubrey Li <aubrey.li@linux.intel.com>
> ---
>   drivers/acpi/prmt.c | 10 +++++++++-
>   1 file changed, 9 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/acpi/prmt.c b/drivers/acpi/prmt.c
> index 1f6007a..89c22bc 100644
> --- a/drivers/acpi/prmt.c
> +++ b/drivers/acpi/prmt.c
> @@ -288,10 +288,18 @@ static acpi_status acpi_platformrt_space_handler(u32 function,
>   
>   void __init init_prmt(void)
>   {
> +	struct acpi_table_header *tbl;
>   	acpi_status status;
> -	int mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
> +	int mc;
> +
> +	status = acpi_get_table(ACPI_SIG_PRMT, 0, &tbl);
> +	if (ACPI_FAILURE(status))
> +		return;
> +
> +	mc = acpi_table_parse_entries(ACPI_SIG_PRMT, sizeof(struct acpi_table_prmt) +
>   					  sizeof (struct acpi_table_prmt_header),
>   					  0, acpi_parse_prmt, 0);
> +	acpi_put_table(tbl);
>   	/*
>   	 * Return immediately if PRMT table is not present or no PRM module found.
>   	 */
> 

Tested-by: Paul Menzel <pmenzel@molgen.mpg.de>


Kind regards,

Paul