* H. Nikolaus Schaller hns@goldelico.com [160914 13:32]:
Hi Tony,
Am 14.09.2016 um 21:43 schrieb Tony Lindgren tony@atomide.com:
Hi,
So what was the root cause of the 1.5GHz mode issue on Pyra?
Well, we do not really know and have not solved it.
One issue we have found is that the feedback line of SMPS3 is wired up wrongly which should be floating according to Palmas data sheet but is connected.
So we think that SMPS1+2+3 runs into problems when switching to triple mode. Which it probably only does at the 1.5GHz OPP because power demand raises significantly.
This is a real hardware bug in the Pyra CPU board but production of a corrected PCB has just started today. So we will need some 2-4 weeks until we can check and compare.
OK
Looks like it's been happening now for past few months with mainline kernel on omap5-uevm.. Does not happen on igepv5.
Yes, that is what I also observe. I have tried today to boot my uevm with letux-4.8-rc6 and it hangs on ~70% of all boot attempts.
When it boots, I can work for some time but an apt-get update did make it hang during the % completion display (where both cores are fully active to scan the package database).
This seems to be exactly the same symptom as for the Pyra.
OK yeah that's what I'm seeing too.
On igepv5 I can compile kernels no problem, but on omap5-uevm things fast hang if I do:
$ dd if=/dev/urandom of=/dev/null & $ dd if=/dev/urandom of=/dev/null &
I have a test script which also prints CPU/GPU temperatures which can rise quite quickly:
http://git.goldelico.com/?p=gta04-kernel.git;a=blob;f=Letux/root/high-load;h... http://git.goldelico.com/?p=gta04-kernel.git;a=blob;f=Letux/root/temperature...
I haven't run it recently but can to tomorrow.
OK
If I comment out the 1.5GHz mode in the dts file it behaves I think.
Yes, I have the same observation on Pyra. I did try to reduce the 1.5Ghz frequency and noticed failure above 1.2GHz. At 1.0GHz it did run completely stable.
OK
Interestingly it seems as if I am the only one with such problems on the uevm. Other Pyra developers with an uevm did not confirm it.
I'm pretty sure things were working fine for me until June this year.
I did update bootloader to the mainline u-boot recently on my uvem.
Do we have an idea what the last version w/o problems is? Or does the latest TI or Robert Nelson kernel work?
I downgraded my bootloader to be same as on igepv5, and I'm still seeing hangs. Maybe not so often though?
I might still have some working uImages where the oldest one with OMAP5 support being the 4.1 kernel:
http://download.goldelico.com/letux-kernel/
If I find time, I will try to boot that.
I'm now wondering if we've had some kernel regression from around May or June.
Regards,
Tony