linux-kernel - Re: [PATCH] platform/x86: thinkpad_acpi: Only update profile if successfully converted

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Message-ID: <f0f64e2d-5e6f-4a3b-b57d-e617142eb08c@redhat.com>
Date: Mon, 19 Feb 2024 13:59:42 +0100
From: Hans de Goede <hdegoede@...hat.com>
To: Mario Limonciello <mario.limonciello@....com>,
 Mark Pearson <mpearson-lenovo@...ebb.ca>
Cc: platform-driver-x86@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] platform/x86: thinkpad_acpi: Only update profile if
 successfully converted

Hi,

On 2/17/24 03:23, Mario Limonciello wrote:
> Randomly a Lenovo Z13 will trigger a kernel warning traceback from this
> condition:
> 
> ```
> if (WARN_ON((profile < 0) || (profile >= ARRAY_SIZE(profile_names))))
> ```
> 
> This happens because thinkpad-acpi always assumes that
> convert_dytc_to_profile() successfully updated the profile. On the
> contrary a condition can occur that when dytc_profile_refresh() is called
> the profile doesn't get updated as there is a -EOPNOTSUPP branch.
> 
> Catch this situation and avoid updating the profile. Also log this into
> dynamic debugging in case any other modes should be added in the future.
> 
> Fixes: c3bfcd4c6762 ("platform/x86: thinkpad_acpi: Add platform profile support")
> Signed-off-by: Mario Limonciello <mario.limonciello@....com>

Thank you for your patch, I've applied this patch to my review-hans 
branch:
https://git.kernel.org/pub/scm/linux/kernel/git/pdx86/platform-drivers-x86.git/log/?h=review-hans

Note it will show up in my review-hans branch once I've pushed my
local branch there, which might take a while.

I will include this patch in my next fixes pull-req to Linus
for the current kernel development cycle.

Regards,

Hans




> ---
> BTW - This isn't new.  I've been seeing this a long time, but I just finally
> got annoyed enough by it to find the code that triggered the sequence.
> 
>  drivers/platform/x86/thinkpad_acpi.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
> index c4895e9bc714..5ecd9d33250d 100644
> --- a/drivers/platform/x86/thinkpad_acpi.c
> +++ b/drivers/platform/x86/thinkpad_acpi.c
> @@ -10308,6 +10308,7 @@ static int convert_dytc_to_profile(int funcmode, int dytcmode,
>  		return 0;
>  	default:
>  		/* Unknown function */
> +		pr_debug("unknown function 0x%x\n", funcmode);
>  		return -EOPNOTSUPP;
>  	}
>  	return 0;
> @@ -10493,8 +10494,8 @@ static void dytc_profile_refresh(void)
>  		return;
>  
>  	perfmode = (output >> DYTC_GET_MODE_BIT) & 0xF;
> -	convert_dytc_to_profile(funcmode, perfmode, &profile);
> -	if (profile != dytc_current_profile) {
> +	err = convert_dytc_to_profile(funcmode, perfmode, &profile);
> +	if (!err && profile != dytc_current_profile) {
>  		dytc_current_profile = profile;
>  		platform_profile_notify();
>  	}