[PATCH v5 00/21] PM / devferq: Add generic exynos bus frequency driver and new passive governor

Hi Tobias,

On Thu, Mar 24, 2016 at 10:52 PM, Tobias Jakobi
[off-list ref] wrote:

Hello everybody,


Markus Reichl wrote:

quoted

Hi Chanwoo,

Am 24.03.2016 um 05:30 schrieb Chanwoo Choi:

quoted

Dear Anand and Tobias,

To Anand,
First of all, thanks to your test on previous patchset.
I removed the your tested-by tag from this version
because I modified the devfreq core using DEVFREQ_TRANSITION_NOTIFIER notifier.
I think that this patch-set need to test with this patchset.
If you possible, could you please test this patch-set? Thanks in advance.

To Tobias,
I fixed the following issues reported by you. Thanks your test and report.
- RCU locking issue
- debugfs error during kernel booting

Best Regards,
Chanwoo Choi

This set works fine on odroid U3 but gives the following with dmesg |grep devfreq:

[    2.066890] devfreq bus_dmc: Couldn't update frequency transition information.
[    2.190238] devfreq bus_leftbus: Couldn't update frequency transition information.

I have yet to test this new iteration of the patchset, but this message
looks familiar. I already encountered it with the older version applied
to vanilla-4.5.y.

The messages happen when devfreq_update_status() (in
drivers/devfreq/devfreq.c) encounters a uninitialized (zero)
previous_freq. I have currently fixed this in my local tree by just
skipping (goto out) devfreq_update_status() in that case.

I agree. Your comment is correct.

Maybe it would be more elegant to set previous_freq to something sane on
probe. IIRC then it is set from initial_freq on probe, but the exynos
code doesn't set this one.

The devfreq have already this issue before sending my patches.
So, I think that you better to send your fixup patch.

Maybe, the exynos-bus.c read the current frequency in the probe function
and then devfreq core should set the devfreq->previous_freq field.

Maybe this info is helpful?

Your info is very helpful. Thanks.

Best Regards,
Chanwoo Choi