lkml.org 
[lkml]   [2009]   [Jul]   [31]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH update] PM: Introduce core framework for run-time PM of I/O devices (rev. 11)
    Date
    On Friday 31 July 2009, Magnus Damm wrote:
    > Hi Rafail

    Hi,

    > [Runtime PM v11]
    >
    > Thanks for your work on this. The code is getting better and better.
    > I've just finished posting a bunch of patches related to v11 of your
    > Runtime PM patch. Basically everything seems fine except a few minor
    > details and the code below: =)

    Thanks a lot for your feedback.

    > On Thu, Jul 23, 2009 at 4:10 AM, Rafael J. Wysocki<rjw@sisk.pl> wrote:
    > > On Wednesday 22 July 2009, Rafael J. Wysocki wrote:
    > > Index: linux-2.6/drivers/base/dd.c
    > > ===================================================================
    > > --- linux-2.6.orig/drivers/base/dd.c
    > > +++ linux-2.6/drivers/base/dd.c
    > > @@ -23,6 +23,7 @@
    > > #include <linux/kthread.h>
    > > #include <linux/wait.h>
    > > #include <linux/async.h>
    > > +#include <linux/pm_runtime.h>
    > >
    > > #include "base.h"
    > > #include "power/power.h"
    > > @@ -202,7 +203,9 @@ int driver_probe_device(struct device_dr
    > > pr_debug("bus: '%s': %s: matched device %s with driver %s\n",
    > > drv->bus->name, __func__, dev_name(dev), drv->name);
    > >
    > > + pm_runtime_get_noresume(dev);
    > > ret = really_probe(dev, drv);
    > > + pm_runtime_put_noidle(dev);
    > >
    > > return ret;
    > > }
    >
    > This creates problems when drivers want to performing runtime resume
    > from within probe(). For more details please have a look at "[PATCH
    > 04/04] video: Runtime PM hack for SuperH LCDC driver".

    Ah, I see. You'd like to call pm_runtime_get_sync() from .probe(), but that
    sees the usage counter different from zero and exits immediately.

    OTOH, I think we should prevent suspends from racing with .probe() at the core
    level. Hmm.

    One possible approach could be to call pm_runtime_resume() from
    sh_mobile_lcdc_probe() instead of pm_runtime_put_noidle(). Then, the platform
    code will have a chance to turn the device on and the later pm_runtime_get*()
    and pm_runtime_put*() calls will be balanced. Of course, in that case the
    pm_runtime_get_noresume() in sh_mobile_lcdc_probe() won't be necessary any
    more. Am I overlooking anything?

    Rafael


    \
     
     \ /
      Last update: 2009-07-31 20:57    [W:0.024 / U:62.268 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site