Date: Thu, 23 May 2013 23:11:49 -0600 From: Warner Losh <imp@bsdimp.com> To: Justin Hibbits <jrh29@alumni.cwru.edu> Cc: freebsd-arch@freebsd.org Subject: Re: late suspend/early resume Message-ID: <780B27A1-AA4F-4382-BE33-7587BD9EB615@bsdimp.com> In-Reply-To: <CAHSQbTDQQz1r%2BpsH3-Z6DESLoenXcjnefsNxZO7NtbboMtJ0rw@mail.gmail.com> References: <CAHSQbTBNjrx=9DT7vk29D=Y%2BOK0qV=Ld4qN-sxy%2B8_OONazKAA@mail.gmail.com> <AE98E779-E22B-434D-9BEE-BF66241BB2E6@bsdimp.com> <51913B7D.1040801@freebsd.org> <288C9B9E-E943-4C5B-BCFB-15B721CBE94C@bsdimp.com> <CAHSQbTCEOfCH5tLeWgP4gPVbsBwDKLKBboQ2d74npkQomoJJJQ@mail.gmail.com> <519369C4.6060402@FreeBSD.org> <CAHSQbTDQQz1r%2BpsH3-Z6DESLoenXcjnefsNxZO7NtbboMtJ0rw@mail.gmail.com>
index | next in thread | previous in thread | raw e-mail
On May 23, 2013, at 11:08 PM, Justin Hibbits wrote: > John, > > > On Wed, May 15, 2013 at 3:56 AM, John Baldwin <jhb@freebsd.org> wrote: > >> On 5/14/13 1:14 PM, Justin Hibbits wrote: >>> You are right that the late suspend could lead to silly proliferation, >> and >>> an ordered list is much better, but another API would need to be added to >>> do that as well. >>> >>> My north bridge is first in the top list of the tree, right under the >>> nexus, so to suspend it last I wrote the nexus suspend to traverse its >>> children in reverse. The problem comes that the clock controller is >> under a >>> later PCI bus, not even the immediate following one, and the north bridge >>> children are i2c devices, so suspending them after their clock head away >> is >>> problematic. We can discuss this more at bsdcan, where it may be easier >> to >>> describe. But essentially I need the north bridge and that pesky clock >>> controller to be the last to suspend and the first to resume. I guess we >>> can take this as the starting discussion for modeling this relationship >> on >>> all platforms, since you mention it is common in embedded platforms. >> >> I think you can do this by having a notion of passes with drivers having >> a suspend pass level and doing passes over the tree suspending devices >> at each pass level and then walking the passes back up in reverse during >> resume. You could borrow from the multipass stuff used on probe/attach >> for this. >> >> -- >> John Baldwin >> > > I have an update in the projects/pmac_pmu branch. It works for my > PowerBook, but I'm not certain how well it will fare in the end, because of > the way the PCI driver resumes its children. It doesn't call > bus_generic_resume(), and instead suspends each child individually, which > can lead to devices being resumed multiple times, but I'm uncertain how to > fix that. Any ideas? One I had was to have some kind of > 'bus_generic_resume_filtered' or similar, that lets bus_generic_resume run > its logic, but filter through a function to determine if the child is > resumable. But that doesn't quite feel right to me. How does it lead there? Did you change the suspend/resume function signatures? Or did you create new ones like I suggested that had a default method that called the old suspend/resume function iff pass was the last one.... Warnerhome | help
Want to link to this message? Use this
URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?780B27A1-AA4F-4382-BE33-7587BD9EB615>