Re: [PATCH v4 00/15] PM QoS: add a per-device latency constraints class

["Rafael J. Wysocki" <rjw@sisk.pl>]

Hi,

On Friday, August 12, 2011, Jean Pihet wrote:
> Hi Rafael,
> 
> 2011/8/12 Rafael J. Wysocki <rjw@sisk.pl>:
> > On Thursday, August 11, 2011, jean.pihet@newoldbits.com wrote:
> >> From: Jean Pihet <j-pihet@ti.com>
> >>
> >> This patch set is in an RFC state, for review and comments.
> >>
> ...
> >>
> >>
> >> Questions:
> >> 1. the user space API is still under discussions on linux-omap and linux-pm MLs,
> >>    cf. [1]. The idea is to add a user-space API for the devices constratins
> >>    PM QoS, using a sysfs entry per device
> >>
> >> [1] http://marc.info/?l=linux-omap&m=131232344503327&w=2
> >>
> >> ToDo:
> >> 1. write Documentation for the new PM QoS class, once the RFC is agreed on
> >> 2. validate the constraints framework on OMAP4 HW (done on OMAP3)
> >> 3. Need testing on platforms other than OMAP
> >> 4. refine the power domains wake-up latency and the cpuidle figures
> >> 5. re-visit the OMAP power domains states initialization procedure. Currently
> >>    the power states that have been changed from the constraints API which were
> >>    applied before the initialization of the power domains are lost
> >>
> >>
> >> Based on the master branch of the linux-omap git tree (3.0.0-rc7). Compile
> >> tested using OMAP and x86 generic defconfigs.
> >>
> >> Lightly tested on OMAP3 Beagleboard (ES2.x).
> >> Need testing on platforms other than OMAP, because of the impact on the
> >> device insertion/removal in device_pm_add/remove
> >
> > The patchset looks really good to me, I don't think I have any major
> > complaints about this version.
> Ok good to hear it! I tried to address all comments and concerns in
> this release.
> 
> >
> > The only thing I'd like to ask at the moment is whether or not the
> > compilation of drivers/base/power/qos.c should depend on
> > CONFIG_PM_RUNTIME.  Do you think it will be used by system suspend code on any
> > platforms?
> I would say it should only depend on CONFIG_PM because the dev PM QoS
> API can be used from any kernel code, being runtime PM code or not.
> I leave the decision to the PM framework experts.
> 
> >
> > Also, I'd like to take the final patchset for 3.2,
> Ok good!
> 
> > but I don't feel
> > confident enough about the OMAP patches.
> The OMAP patches have been reviewed a few times already and the
> comments have been taken into account. Also i has been tested
> correctly on OMAP3.
> 
> > If you want me to take them too,
> > please make sure they are ACKed by the OMAP maintainers.
> For sure I need the Acks. I guess I now need to annoy OMAP folks about it ;p
> In the case the Acks are not gathered on time the generic patches
> could be merged in, then the OMAP generic code. Do you think it is a
> viable option?

Yes, it is.  I can take patches [1-7/15] alone.

> The only concern I have is about the on-going OMAP PM initialization
> clean-up task, cf. ToDo list:
>   >> 5. re-visit the OMAP power domains states initialization
> procedure. Currently
>   >>    the power states that have been changed from the constraints
> API which were
>   >>    applied before the initialization of the power domains are lost
> 
> On the other hand some testing is needed on platforms other than OMAP,
> because of the impact on the device insertion/removal in
> device_pm_add/remove functions. I tested the SD card insertion/removal
> on OMAP3.

OK, so are you going to make any more changes to patches [1-7/15]?

Rafael