linux-kernel - Re: [PATCH] soc: apple: rtkit: Add function to poweroff

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Message-ID: <4c5a8c22-4e96-4780-a083-9326756a4144@kernel.org>
Date: Sat, 17 Jan 2026 18:50:04 +0100
From: Sven Peter <sven@...nel.org>
To: Janne Grunau <j@...nau.net>
Cc: Neal Gompa <neal@...pa.dev>, asahi@...ts.linux.dev,
 linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] soc: apple: rtkit: Add function to poweroff

Hi,

On 1/17/26 18:38, Janne Grunau wrote:
> On Sat, Jan 17, 2026 at 06:24:44PM +0100, Sven Peter wrote:
>> Add a function to put a co-processor into the lowest possible power
>> state from which recovery usually isn't possible without a full SoC
>> reset. This is required for the USB4/Thunderbolt co-processors which
>> can be restarted since the entire USB4 root complex can be completely
>> reset independently of the rest of the SoC.
>>
>> Signed-off-by: Sven Peter <sven@...nel.org>
>> ---
>>   drivers/soc/apple/rtkit.c       | 17 +++++++++++++++++
>>   include/linux/soc/apple/rtkit.h |  7 +++++++
>>   2 files changed, 24 insertions(+)
>>
>> diff --git a/drivers/soc/apple/rtkit.c b/drivers/soc/apple/rtkit.c
>> index b8d4da147d23f7e99e76eea314e4d976cddbd1c6..381faaf74d5982163d2c44d1e2c6e0ddad07bd73 100644
>> --- a/drivers/soc/apple/rtkit.c
>> +++ b/drivers/soc/apple/rtkit.c
>> @@ -851,6 +851,23 @@ int apple_rtkit_shutdown(struct apple_rtkit *rtk)
>>   }
>>   EXPORT_SYMBOL_GPL(apple_rtkit_shutdown);
>>   
>> +int apple_rtkit_poweroff(struct apple_rtkit *rtk)
>> +{
>> +	int ret;
>> +
>> +	ret = apple_rtkit_set_ap_power_state(rtk,
>> +					     APPLE_RTKIT_PWR_STATE_OFF);
>> +	if (ret)
>> +		return ret;
>> +
>> +	ret = apple_rtkit_set_iop_power_state(rtk, APPLE_RTKIT_PWR_STATE_OFF);
> inconsistent line wrapping. It's wrapped for AP power state which is 1
> character shorter. I would wrap neither it only moves the statement 4
> places to the left.

Good catch, will fix it.
>
>> +	if (ret)
>> +		return ret;
>> +
>> +	return apple_rtkit_reinit(rtk);
>> +}
>> +EXPORT_SYMBOL_GPL(apple_rtkit_poweroff);
>> +
>>   int apple_rtkit_idle(struct apple_rtkit *rtk)
>>   {
>>   	int ret;
>> diff --git a/include/linux/soc/apple/rtkit.h b/include/linux/soc/apple/rtkit.h
>> index 736f530180179bd144cf85eb0f0bd93844d7188a..bda3c528b51553c13f7fe5685ab60f7fc675361b 100644
>> --- a/include/linux/soc/apple/rtkit.h
>> +++ b/include/linux/soc/apple/rtkit.h
>> @@ -125,6 +125,13 @@ int apple_rtkit_wake(struct apple_rtkit *rtk);
>>    */
>>   int apple_rtkit_shutdown(struct apple_rtkit *rtk);
>>   
>> +/*
>> + * Put the co-processor into the lowest power state. Note that it usually
>> + * is not possible to recover from this state without a full SoC reset.
>> + */
>> +
>> +int apple_rtkit_poweroff(struct apple_rtkit *rtk);
>> +
>>   /*
>>    * Put the co-processor into idle mode
>>    */
>>
> Feel free to fix without sending a v2
>
> Reviewed-by: Janne Grunau <j@...nau.net>

Thanks! b4 makes sending that v2 very easy luckily :)


Thanks,

Sven