From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mout02.posteo.de (mout02.posteo.de [185.67.36.66]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 005DC2EAB64 for ; Tue, 27 Jan 2026 15:34:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=185.67.36.66 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769528062; cv=none; b=UtIvDesySfIJ9mj59aIMn8oUtlOvxVPKgNNSuFyhX0G87shkWXwCWb/2xJSsmiwHav4Flz2pUDC++j5rMs1xPefyzrDJp6dhs0sycSjuIsS4mDlymof1Qd6AfehVnjBLYF7AKsesfKOZxAymMuKP8vljlbstuc37mswLrtqQ/+0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769528062; c=relaxed/simple; bh=DQ2F9P8gXel5sqSxKC7vJrPwpNY2sFgwvFDvzLpmLHk=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=C5PycqTMixLC0iDU+9JKfVW19+ogHXmz3tx7CIiwZ1QOaJ+9K/nR1Q6Cd1LQJox6jxmCUE33rjkjjEX5nkC0kzl95MLzA0urOhyPd+DmapdL9wbGoTj8bHggiB2vtEAX8FxCosmuWnqm7NMUWi4uRm/cyHUqK/iuJrJoCKOvev8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de; spf=pass smtp.mailfrom=posteo.de; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b=YrDjqjod; arc=none smtp.client-ip=185.67.36.66 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=posteo.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=posteo.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=posteo.de header.i=@posteo.de header.b="YrDjqjod" Received: from submission (posteo.de [185.67.36.169]) by mout02.posteo.de (Postfix) with ESMTPS id 5686D240105 for ; Tue, 27 Jan 2026 16:34:12 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posteo.de; s=2017; t=1769528052; bh=DQ2F9P8gXel5sqSxKC7vJrPwpNY2sFgwvFDvzLpmLHk=; h=Message-ID:Subject:From:To:Cc:Date:Autocrypt:Content-Type: MIME-Version:OpenPGP:From; b=YrDjqjodyTN2o1jhx3pYdrRv4p1dpea4aVqvN3P6yD10/jlRfBL1QgA0CAzwttAIU VcsgjRBKH1nFKRVh0eTwW+uEYAjRbtD8+ZgC/29Q2QJHTeUtA2KE/xVE9l/t8A++NS /ymidxlXfweavFOuK8QrjfYGxYqbiZ979htB+VC8aY+iryVkw3+TL8b3cgx1NrpOdl ERP9wl6siAM200TuzFUBuHZc9jmcP2Ja2cm3pZuwBqkaqDNKLNlep4FQgmZ8XytzGe anF6dqRRSK9T1i7kUVG3aqsitbAPw2W+TosT0doxaVZgXiPQsMDGeoR/gPE5xAVpyj AnTiIOSvVQeuQ== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4f0qFY3Lk8z9rxN; Tue, 27 Jan 2026 16:34:09 +0100 (CET) Message-ID: <20f855baaa7c36010eab9997a2f43b4f62be726b.camel@posteo.de> Subject: Re: [PATCH RFC 0/4] leds: extend disk trigger From: Markus Probst To: Niklas Cassel Cc: Lee Jones , Pavel Machek , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Jacek Anaszewski , Damien Le Moal , John Garry , Jason Yan , "James E.J. Bottomley" , "Martin K. Petersen" , Pavel Machek , linux-leds@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, Ian Pilcher Date: Tue, 27 Jan 2026 15:34:11 +0000 In-Reply-To: References: <20260123-ledtrig_disk_-v1-0-07004756467b@posteo.de> Autocrypt: addr=markus.probst@posteo.de; prefer-encrypt=mutual; keydata=mQINBGiDvXgBEADAXUceKafpl46S35UmDh2wRvvx+UfZbcTjeQOlSwKP7YVJ4JOZrVs93 qReNLkOWguIqPBxR9blQ4nyYrqSCV+MMw/3ifyXIm6Pw2YRUDg+WTEOjTixRCoWDgUj1nOsvJ9tVA m76Ww+/pAnepVRafMID0rqEfD9oGv1YrfpeFJhyE2zUw3SyyNLIKWD6QeLRhKQRbSnsXhGLFBXCqt 9k5JARhgQof9zvztcCVlT5KVvuyfC4H+HzeGmu9201BVyihJwKdcKPq+n/aY5FUVxNTgtI9f8wIbm fAjaoT1pjXSp+dszakA98fhONM98pOq723o/1ZGMZukyXFfsDGtA3BB79HoopHKujLGWAGskzClwT jRQxBqxh/U/lL1pc+0xPWikTNCmtziCOvv0KA0arDOMQlyFvImzX6oGVgE4ksKQYbMZ3Ikw6L1Rv1 J+FvN0aNwOKgL2ztBRYscUGcQvA0Zo1fGCAn/BLEJvQYShWKeKqjyncVGoXFsz2AcuFKe1pwETSsN 6OZncjy32e4ktgs07cWBfx0v62b8md36jau+B6RVnnodaA8++oXl3FRwiEW8XfXWIjy4umIv93tb8 8ekYsfOfWkTSewZYXGoqe4RtK80ulMHb/dh2FZQIFyRdN4HOmB4FYO5sEYFr9YjHLmDkrUgNodJCX CeMe4BO4iaxUQARAQABtCdNYXJrdXMgUHJvYnN0IDxtYXJrdXMucHJvYnN0QHBvc3Rlby5kZT6JAl QEEwEIAD4CGwMFCwkIBwICIgIGFQoJCAsCBBYCAwECHgcCF4AWIQSCdBjE9KxY53IwxHM0dh/4561 D0gUCaIZ9HQIZAQAKCRA0dh/4561D0pKmD/92zsCfbD+SrvBpNWtbit7J9wFBNr9qSFFm2n/65qen NNWKDrCzDsjRbALMHSO8nigMWzjofbVjj8Nf7SDcdapRjrMCnidS0DuW3pZBo6W0sZqV/fLx+AzgQ 7PAr6jtBbUoKW/GCGHLLtb6Hv+zjL17KGVO0DdQeoHEXMa48mJh8rS7VlUzVtpbxsWbb1wRZJTD88 ALDOLTWGqMbCTFDKFfGcqBLdUT13vx706Q29wrDiogmQhLGYKc6fQzpHhCLNhHTl8ZVLuKVY3wTT+ f9TzW1BDzFTAe3ZXsKhrzF+ud7vr6ff9p1Zl+Nujz94EDYHi/5Yrtp//+N/ZjDGDmqZOEA86/Gybu 6XE/v4S85ls0cAe37WTqsMCJjVRMP52r7Y1AuOONJDe3sIsDge++XFhwfGPbZwBnwd4gEVcdrKhnO ntuP9TvBMFWeTvtLqlWJUt7n8f/ELCcGoO5acai1iZ59GC81GLl2izObOLNjyv3G6hia/w50Mw9MU dAdZQ2MxM6k+x4L5XeysdcR/2AydVLtu2LGFOrKyEe0M9XmlE6OvziWXvVVwomvTN3LaNUmaINhr7 pHTFwDiZCSWKnwnvD2+jA1trKq1xKUQY1uGW9XgSj98pKyixHWoeEpydr+alSTB43c3m0351/9rYT TTi4KSk73wtapPKtaoIR3rOFHLQXbWFya3VzLnByb2JzdEBwb3N0ZW8uZGWJAlEEEwEIADsWIQSCd BjE9KxY53IwxHM0dh/4561D0gUCaIO9eAIbAwULCQgHAgIiAgYVCgkICwIEFgIDAQIeBwIXgAAKCR A0dh/4561D0oHZEACEmk5Ng9+OXoVxJJ+c9slBI2lYxyBO84qkWjoJ/0GpwoHk1IpyL+i+kF1Bb7y Hx9Tiz8ENYX7xIPTZzS8hXs1ksuo76FQUyD6onA/69xZIrYZ0NSA5HUo62qzzMSZL7od5e12R6OPR lR0PIuc4ecOGCEq3BLRPfZSYrL54tiase8HubXsvb6EBQ8jPI8ZUlr96ZqFEwrQZF/3ihyV6LILLk geExgwlTzo5Wv3piOXPTITBuzuFhBJqEnT25q2j8OumGQ+ri8oVeAzx24g1kc11pwpR0sowfa5MvZ WrrBcaIL7uJfR/ig7FyGnTQ1nS3btf3p0v8A3fc4eUu/K2No3l2huJp3+LHhCmpmeykOhSB63Mj3s 3Q87LD0HE0HBkTEMwp+sD97ZRpO67H5shzJRanUaDTb/mREfzpJmRT1uuec0X2zItL7a6itgMJvYI KG29aJLX3fTzzVzFGPgzVZYEdhu4y53p0qEGrrC1JtKR6DRPE1hb/OdWOkjmJ75+PPLD9U5IuRd6y sHJWsEBR1F0wkMPkEofWsvMYJzWXx/rvTWO8N4D6HigTgBXAXNgbc3IHpHlkvKoBJptv6DRVRtIrz 0G0cfBY0Sm7he4N2IYDWWdGnPBZ3rlLSdj5EiBU2YWgIgtLrb8ZNJ3ZlhYluGnBJDGRqy2jC9s1jY 66sLA9rQZMHhJTzMyIDwweGlvMzJAcG9zdGVvLmV1PokCbQQTAQgAVxYhBIJ0GMT0rFjncjDEczR2 H/jnrUPSBQJpa71VGxSAAAAAAAQADm1hbnUyLDIuNSsxLjExLDIsMgIbAwULCQgHAgIiAgYVCgkIC wIEFgIDAQIeBwIXgAAKCRA0dh/4561D0gKJD/9uOQKYlsDoQX65Gd0LiMT0C+5vXgr3VI0PHDOwcv 51fJ3A1vNyPZRFPGrz8+mDEXUQOF/INfnz5Tu1QHwf+iYcWcTGAN/FHgVR6ET6VBNU2hJaKhu+Ggo kjYyJTOvyX+3yNRUfSny0GjTjIPuPTErjqmHF+BtjXslpgwqnNMznf3lRIuUjRORupos6p3k1DndE 5vzUTmXSvMyXyOD2KhBl/kL76k0bHYyAQytZPag12pltrtFbA/r2phDGN2si8PooDT99bSTJjaM45 MTAAHbHKJfvgfK41bNFD5mMtpWpL195XRtS0Nrxdg3PaYBxN5gtTG0RyZfpYRlkdEhm+jj/8RxuSG i/qdhRdbiI7K2IELWeQVHSNDi9JabR/UzlR4NSnhfAjRIVlRM+eFbUl8XwxwVrAkojF5IraH2qRvg VCmuFsHUW07FUlrDrzpjXsD73cKppoFGDCdDR0BHJepXbFLS9+AqkT+guRJlnCTg2p+TQtnbwPgKp Vj98JixovCl99zRYTsL2bRNU5+q8iET65VMJ1ydyNanvLd5vI/NqDkXhlXLsGmdaDTtu4R21PkToX dQNGrZ91M9nlIBKw8Y7c7xZ4098qX2b8JX/CxD+gC1r4C8vuA3GkhFLx+KlkON7LyiJPkrePp6Qky jfGillcaQOqFZ3WwVqyzG1BUfTow== Content-Type: multipart/signed; micalg="pgp-sha256"; protocol="application/pgp-signature"; boundary="=-95wXs24+lMxxeIwklhSG" Precedence: bulk X-Mailing-List: linux-scsi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 OpenPGP: url=https://posteo.de/keys/markus.probst@posteo.de.asc; preference=encrypt --=-95wXs24+lMxxeIwklhSG Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2026-01-27 at 10:32 +0100, Niklas Cassel wrote: > On Mon, Jan 26, 2026 at 10:06:02PM +0000, Markus Probst wrote: > > On Mon, 2026-01-26 at 10:00 +0100, Niklas Cassel wrote: > > >=20 > > > Why do we want to have this in kernel space? > > Because there are more than enough devices that could make use of it. > >=20 > > Just search the term "NAS device" and you see rarely any devices for > > which this wouldn't be useful. > >=20 > > The only reason the leds work on those devices currently, is because > > they get shipped with a custom modified kernel by the manufacturer. > > This shouldn't be a requirement for running Linux properly on a NAS > > device with disk leds. >=20 > I understand why you want the feature. I just don't understand why we > should add this feature to the kernel, rather than implement it in > user space. >=20 > Having a user space implementation for your feature would also allow > an upstream kernel, without the need for any custom kernel patches. Only because it can be done in userspace, doesn't mean it should be. >=20 > > > If we want something more complex than what is already there, then it > > > is probably much better handled in user space, considering the amount > > > of possible configuration options. > > A userspace daemon by itself is possible, but I don't think it is the > > best solution. Having an indicator for disk activity on a per-disk > > basis seems like basic led functionality that should be present in the > > kernel. >=20 > There seems to be existing user space applications that handles this, > I think both the daemon I linked to before, which uses /sys/block//s= tat > which is thus per device and not per port, and e.g. this: > https://linux.die.net/man/8/ledmon > https://github.com/md-raid-utilities/ledmon > https://github.com/md-raid-utilities/ledmon/blob/main/src/lib/ahci.c As far as I can tell, this daemon doesn't actually use the LED Subsystem, but instead leds directly connected to the storage controller. But yes, I would be capable of coding such daemon. > > > Basically the same argument as used in: > > > https://lore.kernel.org/linux-nvme/20220227234258.24619-1-ematsumiya@= suse.de/T/#u > > If I understood it corretly, the argument there is that led code > > shouldn't be present in a fast path. > >=20 > > This does not apply to this scenario. >=20 > I think my main concern is that I don't think we should bloat the kernel > for a complex feature that can just as well be implemented in user space. It is still unclear to me if you worry about the complexity in drivers/ata/libata-* or drivers/leds/trigger/ledtrig-disk.c @Pavel,@Lee: I would like to know your opinion on this. Thanks - Markus Probst >=20 >=20 > Kind regards, > Niklas --=-95wXs24+lMxxeIwklhSG Content-Type: application/pgp-signature; name="signature.asc" Content-Description: This is a digitally signed message part -----BEGIN PGP SIGNATURE----- iQJPBAABCAA5FiEEgnQYxPSsWOdyMMRzNHYf+OetQ9IFAml42uAbFIAAAAAABAAO bWFudTIsMi41KzEuMTEsMiwyAAoJEDR2H/jnrUPSj0QP/jBX+51lTUOAQlHdCXB1 cnq3yWDlRE7864F+m33J5Zi3YXSdntJ5rza26ByMmx8liyHJMD5UDdGfz9L93sHM TSv4OClvl/xZ6gFRvaFPqBIL38erO9osMuwKsFVzdA3wwHWKeQWl2ZO3IWSiyRxn xy1U+Zxr6LxQlMENbKfTPmCyo1l6visyMouSYqV2ysJ9p+D1n9I81rvrBZYm1ebt EcPJiWGPzzgsA84NR13qKBjJFmelzJyiF48cYOGM5C1mlE3FjYjiVsyJe4h9FGsu d1kbovKMCuY+QAvtRnbFCeth2o8g6ky3Ij8OPIROhrH2NnA+w/INS8Ok92P8Ewvm CfGMkYVq8KXVhEaEaQRw9yWzLLKAquuLRFQ9oUUF3I3b6hEW4ALJkfWraWOPHA6/ i9gx32NO2Pjo6urNcVBGTIAHUQnKwgsmtpCCX2YsF9/j/Vkq6KWmvxuO9eH2tu49 fbEaehSqRlQnC7Q6ERVb2X4UaQYutytRAIJSloPLbmve44c7dE+kjSS460QY69FC Z8hKNL3H8UPSZFqeKGg77X94FYK8Hepd6ccQ0zEYhtLihVNEBC/Jdf5EIY17K4bN Es0E5bqHZMVAIr62ZxqmUdNI6gmnqxlV32OTp8s4BbpJiSoUbrp7JuUqI98rUdKr ELLweuctc6nLul+zl/4Nl71I =G8+8 -----END PGP SIGNATURE----- --=-95wXs24+lMxxeIwklhSG--