From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id B5116C433EF for ; Wed, 13 Oct 2021 08:42:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9314A60D43 for ; Wed, 13 Oct 2021 08:42:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232968AbhJMIol (ORCPT ); Wed, 13 Oct 2021 04:44:41 -0400 Received: from jabberwock.ucw.cz ([46.255.230.98]:44868 "EHLO jabberwock.ucw.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229902AbhJMIol (ORCPT ); Wed, 13 Oct 2021 04:44:41 -0400 Received: by jabberwock.ucw.cz (Postfix, from userid 1017) id E14DD1C0B80; Wed, 13 Oct 2021 10:42:37 +0200 (CEST) Date: Wed, 13 Oct 2021 10:42:37 +0200 From: Pavel Machek To: Sebastian Andrzej Siewior Cc: Thomas Gleixner , johannes.berg@intel.com, linux-leds@vger.kernel.org Subject: Re: [PATCH] leds: trigger: Disable CPU trigger on PREEMPT_RT Message-ID: <20211013084237.GA13150@amd> References: <20210924111501.m57cwwn7ahiyxxdd@linutronix.de> <20210927142345.GB18276@duo.ucw.cz> <87wnn2av6h.ffs@tglx> <20210927154451.GA17112@duo.ucw.cz> <20210927171802.uak3tbpqaig3mm7m@linutronix.de> <20210927190650.GA13992@duo.ucw.cz> <20210927193424.glrddglskpohbosn@linutronix.de> <20211013080838.GA10864@amd> <20211013083900.g4pqwpov62cm2zsw@linutronix.de> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="a8Wt8u1KmwUX3Y2C" Content-Disposition: inline In-Reply-To: <20211013083900.g4pqwpov62cm2zsw@linutronix.de> User-Agent: Mutt/1.5.23 (2014-03-12) Precedence: bulk List-ID: X-Mailing-List: linux-leds@vger.kernel.org --a8Wt8u1KmwUX3Y2C Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Wed 2021-10-13 10:39:00, Sebastian Andrzej Siewior wrote: > On 2021-10-13 10:08:38 [+0200], Pavel Machek wrote: > > Hi! > Hi, >=20 > > > - The idle loop (x86 or ARM makes no difference) is always invoked wi= th > > > disabled interrupts and so sleeping is a no no on PREEMPT_RT. So a > > > spinlock_t can not be acquired in this context. > >=20 > > Ok, I have reviewed code, and your patch seems like a way forward. Can > > you resubmit it with fixed changelog? >=20 > Could you please point me what to needs to be fixed in the changelog? > I mentioned the read lock which is acquired with disabled interrupts > and this does not work on PREEMPT_RT. The read lock is gone in linux-next now (it was problematic for other reasons and it was not the main problem). Pavel --=20 http://www.livejournal.com/~pavelmachek --a8Wt8u1KmwUX3Y2C Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAmFmm/0ACgkQMOfwapXb+vLpVwCgm/trdV4q/R+64L0Ge3LbfaCo 4xEAnAlDCmFSrzQXjS+ixfjk7JORRD0f =gi7W -----END PGP SIGNATURE----- --a8Wt8u1KmwUX3Y2C--