lkml.org 
[lkml]   [2011]   [Oct]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    SubjectRe: [PATCH 2/5] drivercore: Add driver probe deferral mechanism
    From
    CC Rafael and linux-pm

    On Thu, Oct 13, 2011 at 12:09 PM, Grant Likely
    <grant.likely@secretlab.ca> wrote:
    > On Tue, Oct 11, 2011 at 08:29:18PM +0800, Ming Lei wrote:
    >> On Tue, Oct 11, 2011 at 1:37 AM, Andrei Warkentin <awarkentin@vmware.com> wrote:
    >> > Hi,
    >> >
    >> > ----- Original Message -----
    >> >> From: "Greg KH" <greg@kroah.com>
    >> >> To: "Josh Triplett" <josh@joshtriplett.org>
    >> >> Cc: "G, Manjunath Kondaiah" <manjugk@ti.com>, linux-arm-kernel@lists.infradead.org, "Grant Likely"
    >> >> <grant.likely@secretlab.ca>, linux-omap@vger.kernel.org, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
    >> >> "Dilan Lee" <dilee@nvidia.com>, "Mark Brown" <broonie@opensource.wolfsonmicro.com>, Manjunath@jasper.es
    >> >> Sent: Saturday, October 8, 2011 11:55:02 AM
    >> >> Subject: Re: [PATCH 2/5] drivercore: Add driver probe deferral mechanism
    >> >>
    >> >
    >> > I'm a bit of a fly on the wall here, but I'm curious how this impacts suspend/resume.
    >> > device_initialize->device_pm_init are called from device_register, so certainly this
    >> > patch doesn't also ensure that the PM ordering matches probe ordering, which is bound
    >> > to break suspend, right? Was this ever tested with the OMAP target? Shouldn't the
    >>
    >> Inside device_add(), device_pm_add is called before bus_probe_device,
    >> so the patch can't change the device order in pm list, and just change
    >> the driver probe order.
    >
    > That's the way it works now, but can it be reworked?  It would be

    IMO, it depends on what shape you plan to rework. Currently, the
    deferred probe may found a resource dependency, but I am not sure
    that pm dependency is same with the resource dependency found
    during probe.

    > possible to adjust the list order after successful probe.  However,
    > I'm not clear on the ordering rules for the dpm_list.  Right now it is
    > explicitly ordered to have parents before children, but as already
    > expressed, that doesn't accurately represent ordering constraints for
    > multiple device dependancies.

    Maybe we should understand the correct model of the ordering constraints
    for the multiple device dependancies first, could you give a description or
    some examples about it?

    >
    > So, reordering the list would probably require maintaining the
    > existing parent-child ordering constraint, but to also shift
    > devices (and any possible children?) to be after drivers that are
    > already probed.  That alone will be difficult to implement and get
    > right, but maybe the constraints can be simplified.  It needs some
    > further thought.
    >
    > g.
    >
    >


    thanks,
    --
    Ming Lei
    --
    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to majordomo@vger.kernel.org
    More majordomo info at http://vger.kernel.org/majordomo-info.html
    Please read the FAQ at http://www.tux.org/lkml/

    \
     
     \ /
      Last update: 2011-10-13 16:21    [W:4.871 / U:0.028 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site