Re: [PATCH v2] platform/x86/dell: Set USTT mode according to BIOS after reboot

[Mario Limonciello <superm1@kernel.org>]

On 9/16/25 6:51 AM, Shyam Sundar S K wrote:
> After a reboot, if the user changes the thermal setting in the BIOS, the
> BIOS applies this change. However, the current `dell-pc` driver does not
> recognize the updated USTT value, resulting in inconsistent thermal
> profiles between Windows and Linux.
> 
> To ensure alignment with Windows behavior, read the current USTT settings
> during driver initialization and update the dell-pc USTT profile
> accordingly whenever a change is detected.
> 
> Cc: Yijun Shen <Yijun.Shen@Dell.com>
> Co-developed-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Patil Rajesh Reddy <Patil.Reddy@amd.com>
> Signed-off-by: Shyam Sundar S K <Shyam-sundar.S-k@amd.com>
Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>> ---
>   drivers/platform/x86/dell/dell-pc.c | 9 +++++++++
>   1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/platform/x86/dell/dell-pc.c b/drivers/platform/x86/dell/dell-pc.c
> index 48cc7511905a..becdd9aaef29 100644
> --- a/drivers/platform/x86/dell/dell-pc.c
> +++ b/drivers/platform/x86/dell/dell-pc.c
> @@ -228,6 +228,8 @@ static int thermal_platform_profile_get(struct device *dev,
>   
>   static int thermal_platform_profile_probe(void *drvdata, unsigned long *choices)
>   {
> +	int current_mode;
> +
>   	if (supported_modes & DELL_QUIET)
>   		__set_bit(PLATFORM_PROFILE_QUIET, choices);
>   	if (supported_modes & DELL_COOL_BOTTOM)
> @@ -237,6 +239,13 @@ static int thermal_platform_profile_probe(void *drvdata, unsigned long *choices)
>   	if (supported_modes & DELL_PERFORMANCE)
>   		__set_bit(PLATFORM_PROFILE_PERFORMANCE, choices);
>   
> +	/* Make sure that ACPI is in sync with the profile set by USTT */
> +	current_mode = thermal_get_mode();
> +	if (current_mode < 0)
> +		return current_mode;
> +
> +	thermal_set_mode(current_mode);
> +
>   	return 0;
>   }
>