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Wysocki" , linux-pci@vger.kernel.org References: <20230918130742.GU1599918@black.fi.intel.com> <20230918132424.GA11357@wunner.de> <888824f7-06b5-4df4-ac04-c6cd599ff6f7@amd.com> <20230918142637.GA28754@wunner.de> From: Mario Limonciello In-Reply-To: <20230918142637.GA28754@wunner.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: SA9PR10CA0012.namprd10.prod.outlook.com (2603:10b6:806:a7::17) To DS7PR12MB6095.namprd12.prod.outlook.com (2603:10b6:8:9c::19) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS7PR12MB6095:EE_|SA1PR12MB8967:EE_ X-MS-Office365-Filtering-Correlation-Id: bf217673-1b0f-442b-a482-08dbb856e23c X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0; X-Microsoft-Antispam-Message-Info: eJY4EYczkA1HvmVEJq9XA7ysDboMkSaF8rVSrD8+3HKfcjdDm1yiW2O5wCZiafaO7J9icQ3hW1VBi5qM2GQF6148P4gW6wWD8pOKG53RVFNCKNlYkNyz5wAWR95LV7DzXILcrisJE9DNc6fSByan0IOH2xi0J1H3PyWHcdnJgw3kjauYoYuy4eNQxAR+o+sVVefruUaLphgQ8+VZjEh/AozWiNEr/Bk9BOxQWClJVBkQtcYLno1BTWR6v29R4wVKZSd/qy/Z0z3W6aqvvLvuvEav8rx+xFB42bQhltLdh4ZKmk/8Jpx1s6tGiOwuJjc2YDXMf4D8VAeCcm6n0bb1eZ27w+A5VKQwfEtJIlKA9A0Ygb6Tt0mrVnM1DsjkQeuQzBx3tF31LdPCbxYjDl7DPPFT8Ef6j7cT+yeWthELE4b/+xU+mErilW7o3PopjGFxzElBXYpgiwxx99lWkQCdHmMoHVSrooZw+gnF9j2yV/bU3KUbh35Dambj1kiE0L6tZk94Yz8pYih+W90F2F6w/UinK3bHgQIZ6D8WthALWVy3Dz7HfDewsjq7YVwSSBNqE5d9aPAz6CT+Fnxgdw68qH0vapWsc5JYGpJLW0mL+tgzESK/T5TcJkKvinsWZxWJgMQPvvIDSG7e3qjTEMBsCttSKnqPaOAntazS71e/xw4= X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:DS7PR12MB6095.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230031)(136003)(366004)(346002)(396003)(376002)(39860400002)(1800799009)(186009)(451199024)(26005)(2616005)(8936002)(8676002)(4326008)(83380400001)(2906002)(36756003)(31696002)(5660300002)(44832011)(86362001)(53546011)(6506007)(6486002)(478600001)(31686004)(6916009)(316002)(54906003)(6512007)(38100700002)(66946007)(66476007)(41300700001)(66556008)(32563001)(45980500001)(43740500002);DIR:OUT;SFP:1101; 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Then commit 4f9c1397e2e8 >>> ("PCI/PM: Enable D3/D3cold by default for most devices") changed >>> the default to "true". That was 11 years ago. >>> >>> I agree that today this should all work automatically and a >>> user space option to disable D3cold on a per-device basis only >>> really makes sense as a debugging aid, hence belongs in debugfs. >>> >> >> Thanks. Then perhaps as part of moving it to debugfs it makes sense to >> simplify the logic. > > d3cold_allowed is documented in Documentation/ABI/testing/sysfs-bus-pci, > so it's user space ABI which we're not allowed to break. We'd have to > declare it deprecated, emit a warning when it's used and slowly phase > it out over the years. What about as part of deprecating it to make it always return -EINVAL no matter the input? The ABI isn't broken, but it allows for the optimization. > > Until then, the $SUBJECT_PATCH probably still makes sense to reinstate > the behavior we had until 2016... > > Thanks, > > Lukas