From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marek Szyprowski Subject: Re: [PATCH v6 0/5] Functional dependencies between devices Date: Tue, 08 Nov 2016 07:36:45 +0100 Message-ID: <23e4a2bd-41d4-5e14-9539-2acf326dd534@samsung.com> References: <27296716.H9VWo8ShOm@vostro.rjw.lan> <11468990.WB1J8sxXpS@vostro.rjw.lan> <20161031174703.GA25633@kroah.com> <20161107211526.GG1764@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-reply-to: <20161107211526.GG1764@wotan.suse.de> Sender: linux-kernel-owner@vger.kernel.org To: "Luis R. Rodriguez" Cc: Greg Kroah-Hartman , "Rafael J. Wysocki" , Linux PM list , Alan Stern , Linux Kernel Mailing List , Tomeu Vizoso , Mark Brown , Lukas Wunner , Kevin Hilman , Ulf Hansson , Joerg Roedel , Jiri Kosina , Jiri Slaby , Andrzej Hajda , Laurent Pinchart , Lars-Peter Clausen , Grant Likely List-Id: linux-pm@vger.kernel.org Hi Luis, On 2016-11-07 22:15, Luis R. Rodriguez wrote: > On Wed, Nov 02, 2016 at 08:58:38AM +0100, Marek Szyprowski wrote: >> On 2016-10-31 18:47, Greg Kroah-Hartman wrote: >>> On Sun, Oct 30, 2016 at 05:22:13PM +0100, Rafael J. Wysocki wrote: >>>> Let me quote from the previous intro messages for this series first: >>>> >>>>>> Time for another update. :-) >>>>>> >>>>>> Fewer changes this time, mostly to address issues found by Lukas and >>>>>> Marek. >>>>>> >>>>>> The most significant one is to make device_link_add() cope with the case >>>>>> when >>>>>> the consumer device has not been registered yet when it is called. The >>>>>> supplier device still is required to be registered and the function will >>>>>> return NULL if that is not the case. >>>>>> >>>>>> Another significant change is in patch [4/5] that now makes the core apply >>>>>> pm_runtime_get_sync()/pm_runtime_put() to supplier devices around the >>>>>> probing of a consumer one (in analogy with the parent). >>>>> One more update after some conversations during LinuxCon Europe. >>>>> >>>>> The main point was to make it possible for device_link_add() to figure out >>>>> the initial state of the link instead of expecting the caller to provide it >>>>> which might not be reliable enough in general. >>>>> >>>>> In this version device_link_add() takes three arguments, the supplier and >>>>> consumer pointers and flags and it sets the correct initial state of the >>>>> link automatically (unless invoked with the "stateless" flag, of course). >>>>> The cost is one additional field in struct device (I moved all of the >>>>> links-related fields in struct device to a separate sub-structure while at >>>>> it) to track the "driver presence status" of the device (to be used by >>>>> device_link_add()). >>>>> >>>>> In addition to that, the links list walks in the core.c and dd.c code are >>>>> under the device links mutex now, so the iternal link spinlock is not needed >>>>> any more and I have renamed symbols to distinguish between flags, link >>>>> states and device "driver presence statuses". >>>> The most significant change in this revision with respect to the previous one is >>>> related to the fact that SRCU is not available on some architectures, so the >>>> code falls back to using an RW semaphore for synchronization if SRCU is not >>>> there. Fortunately, the code changes needed for that turned out to be quite >>>> straightforward and confined to the second patch. >>>> >>>> Apart from this, the flags are defined using BIT(x) now (instead of open coding >>>> the latter in the flag definitions). >>>> >>>> Updated is mostly patch [2/5]. Patches [1,3,5/5] have not changed (except for >>>> trivial rebasing) and patch [4/5] needed to be refreshed on top of the modified >>>> [2/5]. >>>> >>>> FWIW, I've run the series through 0-day which has not reported any problems >>>> with it. >>> Great, they are now applied to my tree, thanks again for doing this >>> work. >> Thanks for merging those patches! Could you provide a stable tag with them, >> so I can >> ask Joerg to merge my Exynos IOMMU PM patches on top of it via IOMMU tree? > You want these patches to be merged into stable?! This is a whole new set of > functionality, the patches in no way describe any *fixes* or critical issues, > why are you saying this is needed? What makes you believe this is a stable > candidate? I don't want to merge those patches to stale kernel release. By 'stable tag' I just meant something that can be pulled by Joerg to have a base for my Exynos IOMMU patches. Best regards -- Marek Szyprowski, PhD Samsung R&D Institute Poland