On 6/15/20 1:45 PM, Marek Szyprowski wrote:
Hi Lukasz
On 10.06.2020 16:30, Lukasz Luba wrote:
On 6/10/20 3:09 PM, Marek Szyprowski wrote:
On 10.06.2020 16:02, Krzysztof Kozlowski wrote:
On Wed, Jun 10, 2020 at 02:18:12PM +0100, Lukasz Luba wrote:
Hi Krzysztof, Bartek,
I recall that you have been working on some cpuidle code for
Exynos(4?).
I have a question regarding CPUIdle driver for Odroid XU4.
I use the board with LISA tests for EAS, but missing at
least idle state 0 cause errors (please see the log below).
Currently the system does not report any idle driver and the state 0
is missing in: /sys/devices/system/cpu/cpu0/cpuidle/state0/
The state 0 long time ago was WFI. It was kind of meaningless so it it
was dropped.
I am using driver CONFIG_ARM_BIG_LITTLE_CPUIDLE but the
boot stops silently while trying to init the cpu idle devices in
there.
I carry on with a workaround that just removes idle state[1] and set
state_count=1 in the big and little structures.
Try earlyprintk.
In general, the big-little cpuidle driver should work... or rather:
long
time ago it was working. It requires proper support from early stages
(BL1, secure monitor) but this should be already in standard Odroid.
I just saw there:
/* Start at index 1, index 0 standard WFI */
so maybe it was not updated properly to removal of WFI?
I think no one uses this driver so it might be not well tested and not
that useful.
I think it never worked on Odroid XU3/XU4. Afair it was developed on
PeachPi Chromebook, which use different bootloader (and doesn't use
trustzone).
That would explain the compatibility string in that driver. Good to
know. Thank you for your response.
I've just digged a bit in the old kernels and indeed, the big-little
cpuidle driver worked only on Samsung Exynos 5420/5800 Chromebooks
(Peach Pit/Pi). The last release which worked fine (although it was
still not enabled in the exynos_defconfig) is v4.2. Then it got broken
by the commit 833b5794e330 ("ARM: EXYNOS: reset Little cores when cpu is
up"). It never worked on the Odroid XU3/XU4.
Thank you Marek for your time to investigate it. In this case I think
there is no way to fix idle state 1 for Odroid xu3/xu4. I don't have
Peach Pit/Pi so I have to pass, but I can help you in reviewing
if you or someone else have time (and board) to work on it.
Do you have any plans to fix it?
I'm baking some patch internally which might help Odroid XU3/4 though.
If that won't be killed, I'll post it soon.
If failed internally, I will also let you know.
Regards,
Lukasz
Best regards
