From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH v3 0/9] PM / Domains: Fix race conditions during boot Date: Fri, 24 Oct 2014 17:18:04 +0100 Message-ID: <20141024161804.GH3729@sirena.org.uk> References: <1413208930-26019-1-git-send-email-ulf.hansson@linaro.org> <7hd29h8n0o.fsf@deeprootsystems.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="YrlhzR9YrZtruaFS" Return-path: Content-Disposition: inline In-Reply-To: <7hd29h8n0o.fsf@deeprootsystems.com> Sender: linux-samsung-soc-owner@vger.kernel.org To: Kevin Hilman Cc: Ulf Hansson , "Rafael J. Wysocki" , Len Brown , Pavel Machek , linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Geert Uytterhoeven , Alan Stern , Greg Kroah-Hartman , Tomasz Figa , Simon Horman , Magnus Damm , Ben Dooks , Kukjin Kim , Philipp Zabel , Wolfram Sang , Russell King , Dmitry Torokhov , Jack Dai , Jinkun Hong , Aaron Lu , Sylwester Nawrocki List-Id: linux-pm@vger.kernel.org --YrlhzR9YrZtruaFS Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Oct 24, 2014 at 09:12:39AM -0700, Kevin Hilman wrote: > Ulf Hansson writes: > > There may be more than one device in a PM domain which then will be > > probed at different points in time. > > Depending on timing and runtime PM support, in for the device related > > driver/subsystem, a PM domain may be advised to power off after a > > successful probe sequence. > > A general requirement for a device within a PM domain, is that the > > PM domain must stay powered during the probe sequence. To cope with > > such requirement, let's add two new APIs, dev_pm_domain_get|put(). > I'm confused. Why arent' pm_runtime_get*() and pm_runtime_put*() working? > What's not explained here (or what I'm not understanding) is why a PM > domain is powering off if it has active devices. The issue AIUI is what happens during system boot - if one device in a domain probes and marks itself runtime idle then that will trigger domain powerdown even if there is another device in the domain that hasn't yet been probed. This can cause undesirable glitches (or worse) during boot depending on what's getting powered down. --YrlhzR9YrZtruaFS Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBAgAGBQJUSnu8AAoJECTWi3JdVIfQDp4H/1EXWijrstvdfCAo+WZNyJ3+ cvGmhefyGdlL89BIMVvyel8eVdZiZ3wYfFr64Udsfdpq/TGY/rMkpqavBZLMvst2 Bz+MnbLxH/K5qhhL7URujYm8npwN76M09IGtwV/jbwNMnNTCOrw3iV2HeRP2jokv 4fyZppsU8nTtxRFXlbVqwSFf7mI0AD4xnmJivxKU6tEy9+kJWWjv1DttYVe7bPFl wWgnfjEYPzSQkTgKoAzP5AQ0HmR36TExI8+sZWzrMVSYwgoJ9WQor0jsG/3FQ3ZW jnRSDp1dAfAw+y7DCBipfyeTML1WgqH42q96CI+oaMwexD/C6HSIEnjDOVzaH8Y= =tHfU -----END PGP SIGNATURE----- --YrlhzR9YrZtruaFS-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: broonie@kernel.org (Mark Brown) Date: Fri, 24 Oct 2014 17:18:04 +0100 Subject: [PATCH v3 0/9] PM / Domains: Fix race conditions during boot In-Reply-To: <7hd29h8n0o.fsf@deeprootsystems.com> References: <1413208930-26019-1-git-send-email-ulf.hansson@linaro.org> <7hd29h8n0o.fsf@deeprootsystems.com> Message-ID: <20141024161804.GH3729@sirena.org.uk> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 24, 2014 at 09:12:39AM -0700, Kevin Hilman wrote: > Ulf Hansson writes: > > There may be more than one device in a PM domain which then will be > > probed at different points in time. > > Depending on timing and runtime PM support, in for the device related > > driver/subsystem, a PM domain may be advised to power off after a > > successful probe sequence. > > A general requirement for a device within a PM domain, is that the > > PM domain must stay powered during the probe sequence. To cope with > > such requirement, let's add two new APIs, dev_pm_domain_get|put(). > I'm confused. Why arent' pm_runtime_get*() and pm_runtime_put*() working? > What's not explained here (or what I'm not understanding) is why a PM > domain is powering off if it has active devices. The issue AIUI is what happens during system boot - if one device in a domain probes and marks itself runtime idle then that will trigger domain powerdown even if there is another device in the domain that hasn't yet been probed. This can cause undesirable glitches (or worse) during boot depending on what's getting powered down. -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 473 bytes Desc: Digital signature URL: