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b=Q4W0wHoYbsjqkKcx5GWDZrEGTVkDQRHD08jF8Kxo6JgmzHlcQUWhyQXbLs8VrBvPki6xycnu0T4FL+CFU0XoFpKY1e3KnTX2NVOfC1ufd1GTcQYjBHuWoXGaOMB4h50ppXn5b6SOA+RsKLCtLp8970Sh5rthKN6pK9pqKZQDNEU= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=amd.com; Received: from MW4PR12MB6921.namprd12.prod.outlook.com (2603:10b6:303:208::8) by DS6PR12MB851160.namprd12.prod.outlook.com (2603:10b6:8:416::24) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.406.7; Fri, 11 Sep 2026 15:12:38 +0000 Received: from MW4PR12MB6921.namprd12.prod.outlook.com ([fe80::cbf7:e2db:1d37:c83b]) by MW4PR12MB6921.namprd12.prod.outlook.com ([fe80::cbf7:e2db:1d37:c83b%5]) with mapi id 15.21.0406.007; Fri, 11 Sep 2026 15:12:37 +0000 Message-ID: <2d4b2c51-ac5f-4fbc-82aa-8d573d095687@amd.com> Date: Fri, 11 Sep 2026 10:12:34 -0500 User-Agent: Mozilla Thunderbird Beta Subject: Re: [PATCH 2/3] HID: valve-index: Reboot headset on system power transitions To: Greg Kroah-Hartman , Michal Pecio Cc: Jiri Kosina , Benjamin Tissoires , Pierre-Loup Griffais , open list , "open list:HID CORE LAYER" , "open list:USB SUBSYSTEM" , Curtis Vogt References: <20260910170254.833871-1-mario.limonciello@amd.com> <20260910170254.833871-3-mario.limonciello@amd.com> <2026091133-silliness-recollect-e190@gregkh> <20260911111652.703b865f.michal.pecio@gmail.com> <2026091106-footing-antelope-7ceb@gregkh> Content-Language: en-US From: Mario Limonciello In-Reply-To: <2026091106-footing-antelope-7ceb@gregkh> Content-Type: text/plain; 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Writing a boolean false value has no >>>> + effect. This file is write-only. >>> >>> Shouldn't this just be a debugfs file? Making it a sysfs file seems >>> "risky" as it's not a normal operation. >> >> Not sure what's "risky" about it, it's hopefully a root-only thing? >> >> And it's the only supported way for userspace to recover buggy devices >> from certain failure condition, it's been suggested that this could be >> run by udev scripts. Isn't it more "risky" to ask userspace to mount >> and tinker with debugfs as a matter of routine? > > You are creating an "odd" user/kernel api that is used for debugging, > that's not what sysfs is for. sysfs is to show attributes that a device > has NOT to cause the device to go off and do some random thing (yes, > there are exceptions, but generally that's the rule.) > > debugfs is "do whatever you want", so that's a better place for this. > > thanks, > > greg k-h I suppose an alternative path we can build to all of this reset handling at power state transitions and sysfs/debugfs is a callback system for a failed EDID read. Something like DRM drivers can send a notify to a global queue when an EDID read failed. Other drivers could subscribe to that notify and react. I guess this would only work if the USB reset sequence to the HMD looks like an HPD event to DRM though. Also it wouldn't be perfect. If the HMD was connected and the read failed on an unrelated monitor on the system the HMD would reset needlessly. Eh, I think I'm talking myself back into this approach the patch does now. I have no qualms moving the on demand knob to debugfs.