Hi Thomas,
On Fri, Aug 29, 2014 at 5:52 AM, Thomas Abraham ta.omasab@gmail.com wrote:
Hi Kevin,
On Wed, Aug 27, 2014 at 3:55 AM, Kevin Hilman khilman@linaro.org wrote:
On Tue, Aug 26, 2014 at 8:15 AM, Kevin Hilman khilman@linaro.org wrote:
On Mon, Aug 25, 2014 at 10:25 PM, Chander Kashyap k.chander@samsung.com wrote:
[...]
Can you clarify how you're setting the voltages to ensure stability?
below is the diff : wip/exynos/integ
Thanks.
I've applied your patch, and bootup shows vdd_arm and vdd_kfc at 1500mV, but still when booting with cpuidle enabled (bL switcher disabled), I'm seeing lockups with no kernel output. With CPUidle disabled, things are pretty stable.
What tree are you using to test this out on 5420? I'm using mainline v3.17-rc1 + DT patch for CPUidle and this cpufreq series. See my wip/exynos/integ branch at git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux.git.
I mis-stated this. Actually my tree is based on the v3.17-rc1 branch of the exynos-reference tree[1] + the above mentioned patches for cpuidle and cpufreq.
Also, I've narrowed down the instability a bit, and it's not related to CPUidle. I can now trigger a boot hang even without CPUidle enabled. Here's a quick way to cause a boot lockup. With the switcher disabled, I enable CPUfreq and set the default governor to performance. As soon as cpufreq driver loads, it tries to use the top frequences for both clusters, and it hangs.
Selectively disabling frequencies, I narrowed it down to the 1.3GHz and 1.2GHz frequencies of the little cluster. With these commented out in the DT, it will fully boot with the performance governor enabled.
So that leads to the question. Are all of the operating points in exynos5420.dtsi valid for exynos5800, and have they been validated?
I tried to recreate the boot lockup issue using the same steps you listed above for the Exynos5800 peach-pi platform (Chromebook2), but I do not see any issues. I can see both clusters with max clock speed after boot (1.8GHz and 1.3GHz).
I am using v3.17-rc2 + CPUFreq Patches + max77802 regulator support patches for Chromebook2 + temp hack to set A15 voltage to 1.35V and A7 voltage to 1.3V.
Can you share your branch and temp hack(s) as well as your defconfig?
I'm using the v3.17-rc1 branch from the exynos tree (which includes the max77802 series) but also has a bunch of other stuff which may be causing the issue.
It would be good if I can reproduce your exact tree/branch and see if I still have the same problem.
Thanks for looking into this,
Kevin