From owner-svn-src-projects@FreeBSD.ORG Mon Sep 23 19:23:58 2013 Return-Path: Delivered-To: svn-src-projects@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTP id 2D2A7551; Mon, 23 Sep 2013 19:23:58 +0000 (UTC) (envelope-from chmeeedalf@gmail.com) Received: from mail-ie0-x229.google.com (mail-ie0-x229.google.com [IPv6:2607:f8b0:4001:c03::229]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (No client certificate requested) by mx1.freebsd.org (Postfix) with ESMTPS id DEB2C237E; Mon, 23 Sep 2013 19:23:57 +0000 (UTC) Received: by mail-ie0-f169.google.com with SMTP id tp5so7502268ieb.28 for ; Mon, 23 Sep 2013 12:23:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:sender:in-reply-to:references:date:message-id:subject :from:to:cc:content-type; bh=gvC1V6AebhWCro4tH8TmXT0FBZ6qu3Jq5CH4xMy1Hfw=; b=U7QAAtni6ubiYUpYOTjxZ2MEQq/e+SbCrZxrLo5uQv/F1aIVRs1BrZ9LpmVSiyKbvs +m0QydkY17cOdtQ0R1fvE+hAs+sbX0tQMFRG089Cs2RhGiQ887MZBBECj1357u7zcdi2 ZngM/8Sdi/aWITCzIPklZHM51yKEqfK/tr/3hUHF07bqX5WLl8kWeC7dP5wEdv9o+A0d AAZtzOWo9z3hfX1LUYZpXg3ww1emI1pdKEqv7szdWlmoW8K8OUJuDZ+dbXoG3OBordMa n3ZUdNVuiu0wvYSt830uZvCnZvytIpPPhGykVq+qFA/Q8kuk9q6qy7ReYvhYeYhXE/0f g7SQ== MIME-Version: 1.0 X-Received: by 10.42.223.134 with SMTP id ik6mr14771530icb.4.1379964234597; Mon, 23 Sep 2013 12:23:54 -0700 (PDT) Sender: chmeeedalf@gmail.com Received: by 10.64.82.196 with HTTP; Mon, 23 Sep 2013 12:23:54 -0700 (PDT) In-Reply-To: <201305240849.27877.jhb@freebsd.org> References: <201305240358.r4O3wVw5026183@svn.freebsd.org> <201305240849.27877.jhb@freebsd.org> Date: Mon, 23 Sep 2013 12:23:54 -0700 X-Google-Sender-Auth: W7oSOla3wCLH_HqUnltKQKfEuW0 Message-ID: Subject: Re: svn commit: r250956 - projects/pmac_pmu/sys/kern From: Justin Hibbits To: John Baldwin Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.14 Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org X-BeenThere: svn-src-projects@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "SVN commit messages for the src " projects" tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 23 Sep 2013 19:23:58 -0000 Hi John, I know it's an ancient thread I'm replying to, but it's the same thing. On Fri, May 24, 2013 at 5:49 AM, John Baldwin wrote: > On Thursday, May 23, 2013 11:58:31 pm Justin Hibbits wrote: > > Author: jhibbits > > Date: Fri May 24 03:58:31 2013 > > New Revision: 250956 > > URL: http://svnweb.freebsd.org/changeset/base/250956 > > > > Log: > > Add multipass for suspend/resume. This allows some devices to be > resumed before > > others, even their peers, as required by PowerPC Mac hardware. > > I think this is a good start. One question I have is why not reuse the > pass number > from the driver instead of stuffing it in the devclass? (It is > conceivable that > different drivers with different passes might share a devclass even, > though unlikely). > > That is, can't you use child->driver->dl_pass directly? (If a child > doesn't have a > driver it can't suspend or resume anyway). > > Also, can you explain the EAGAIN logic? It's not obvious. Is this how > you are > enforcing that already resumed drivers keep traversing their tree in > subsequent > passes (if not you need to deal with that in some fashion). > > I think we might want to be more explicit about forcing suspend and resume > to > traverse the tree for each pass. The boot-time probe has a BUS_NEW_PASS > callback > it uses for this, and bus_generic_new_pass() is what it uses for that. I > think > you might want to create BUS_SUSPEND_PASS and BUS_RESUME_PASS with generic > versions similar to bus_generic_new_pass. You would check the DF_SUSPENDED > flag there to decide whether or not you wanted to call > BUS_SUSPEND/RESUME_PASS > or DEVICE_SUSPEND(). > > The other thing that makes this more complicated is that unlike > probe/attach, > we might need to actually ask the bus to suspend and resume the device so > that > the bus can do power management. Right now this works because the bus > devices > suspend everything in one pass so they can order things correctly (e.g. > pci_suspend()). If we want to shut down some devices early we might > consider > having a new bus_if method which takes a child and handles suspending that > specific child (it would call DEVICE_SUSPEND). For PCI you might get > something > like this: > > int > pci_suspend_child(device_t bus, device_t child) > { > struct pci_devinfo *dinfo; > int error; > > dinfo = device_get_ivars(child); > pci_cfg_save(child, dinfo, 0); > error = DEVICE_SUSPEND(child); > if (error) > return (error); > if (pci_do_power_suspend) > /* set power state for just this child to D3 */ > return (error); > } > > I need to think a bit more, but I think this is more of a correct model to > handle > passes, and will also be cleaner for suspend/resume in general. > > -- > John Baldwin > Have you had any time to put more thought into imrpoving this? I've fixed I think the last few bugs with the PowerPC-side of things, and want to push this into HEAD after the thaw. Warner had mentioned in a peer thread that a second interface, to pass the bus pass along, with a default of calling the existing bus_resume(). Thoughts? - Justin