Re: [PATCH] platform/x86: asus-wmi: Fix driver not binding when fan curve control probe fails

From: Hans de Goede <hdegoede@redhat.com>
To: Mark Gross <markgross@kernel.org>, Andy Shevchenko <andy@kernel.org>
Cc: acpi4asus-user@lists.sourceforge.net,
	platform-driver-x86@vger.kernel.org,
	"Luke D . Jones" <luke@ljones.dev>
Subject: Re: [PATCH] platform/x86: asus-wmi: Fix driver not binding when fan curve control probe fails
Date: Wed, 27 Apr 2022 16:15:52 +0200	[thread overview]
Message-ID: <58704fe9-5621-018a-9dfd-9e26bc612992@redhat.com> (raw)
In-Reply-To: <20220427114956.332919-1-hdegoede@redhat.com>

Hi,

On 4/27/22 13:49, Hans de Goede wrote:
> Before this commit fan_curve_check_present() was trying to not cause
> the probe to fail on devices without fan curve control by testing for
> known error codes returned by asus_wmi_evaluate_method_buf().
> 
> Checking for ENODATA or ENODEV, with the latter being returned by this
> function when an ACPI integer with a value of ASUS_WMI_UNSUPPORTED_METHOD
> is returned. But for other ACPI integer returns this function just returns
> them as is, including the ASUS_WMI_DSTS_UNKNOWN_BIT value of 2.
> 
> On the Asus U36SD ASUS_WMI_DSTS_UNKNOWN_BIT gets returned, leading to:
> 
>   asus-nb-wmi: probe of asus-nb-wmi failed with error 2
> 
> Instead of playing whack a mole with error codes here, simply treat all
> errors as there not being any fan curves, fixing the driver no longer
> loading on the Asus U36SD laptop.
> 
> Fixes: e3d13da7f77d ("platform/x86: asus-wmi: Fix regression when probing for fan curve control")
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=2079125
> Cc: Luke D. Jones <luke@ljones.dev>
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>

I've added this to my review-hans (soon to be for-next) branch now.

Regards,

Hans

> ---
>  drivers/platform/x86/asus-wmi.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
> index 2104a2621e50..20efcf82ce8d 100644
> --- a/drivers/platform/x86/asus-wmi.c
> +++ b/drivers/platform/x86/asus-wmi.c
> @@ -2223,9 +2223,10 @@ static int fan_curve_check_present(struct asus_wmi *asus, bool *available,
>  
>  	err = fan_curve_get_factory_default(asus, fan_dev);
>  	if (err) {
> -		if (err == -ENODEV || err == -ENODATA)
> -			return 0;
> -		return err;
> +		pr_debug("fan_curve_get_factory_default(0x%08x) failed: %d\n",
> +			 fan_dev, err);
> +		/* Don't cause probe to fail on devices without fan-curves */
> +		return 0;
>  	}
>  
>  	*available = true;