Re: [RFC 0/4] OMAP Cpuidle/Suspend Cleanups

[Rajendra Nayak <rnayak@ti.com>]

On Friday 20 July 2012 02:29 PM, Tero Kristo wrote:
> On Fri, 2012-07-20 at 11:34 +0530, Rajendra Nayak wrote:
>> Hi,
>>
>> Here are some CPUidle/Suspend cleanup patches done by adding
>> some more functionality in the OMAP Powerdomain framework.
>> They mostly cleanup OMAP3 but the same ideas can be used/
>> applied for OMAP4 and beyond.
>>
>> The series is based off Teros' series [1] to add usecounting
>> support within the OMAP Powerdomain framework.
>>
>> The patches are tested with RET/OFF in CPUidle and Suspend
>> on 3630 beagle Xm and 3430 SDP.
>
> This set looks good to me, just requires careful testing that you don't
> break anything as you are moving lots of stuff around. For debugging
> purposes (maybe also permanently?), it might be good to keep some sort
> of failsafe mechanism in place that prevents actual core / per off
> transitions in case there is a problem with the usecounting, and you
> accidentally hit core / per off even though the usecounting doesn't
> expect it (some autoidle mechanism is overlooked for example.)
>
> Maybe add some caching for the programmed next state, and only program
> the HW register once we get to the callbacks, and restore the next state
> to ON after leaving...? This should get rid of any unexpected hangs.ly

Thats exactly what I have been thinking too. The caching is turning out
to be a little tricky though. But something like that would certainly be
needed, and should also get rid of unwanted (multiple) target state
programming.

>
> -Tero
>
>>
>> regards,
>> Rajendra
>>
>> [1] http://www.mail-archive.com/linux-omap@vger.kernel.org/msg72163.html
>>
>> Rajendra Nayak (4):
>>    ARM: OMAP3: cpuidle: Remove unused MPU OSWR support code
>>    ARM: OMAP: PM: Get rid of Powerdomain book-keeping from cpuidle
>>    ARM: OMAP: powerdomain: Add .power_on/.power_down hooks for
>>      powerdomains
>>    ARM: OMAP3: PM: Use .power_on/.power_down to clean omap_sram_idle
>>
>>   arch/arm/mach-omap2/omap-mpuss-lowpower.c |    4 +-
>>   arch/arm/mach-omap2/pm34xx.c              |  158 ++++++++++++++---------------
>>   arch/arm/mach-omap2/powerdomain.c         |   40 ++++----
>>   arch/arm/mach-omap2/powerdomain.h         |    8 +-
>>   arch/arm/mach-omap2/sleep34xx.S           |    4 +-
>>   5 files changed, 104 insertions(+), 110 deletions(-)
>>
>
>