Am Wed, 14 Sep 2016 13:49:14 -0700 hat Tony Lindgren tony@atomide.com geschrieben:
Hi Tony and Nikolaus,
okay, I had a little chat with aTc right now, who has a Pyra prototype and also has issues booting it with a stock 5V AC adaptor (and without battery).
I think we made quite a huge step with that issue.
As mentioned, some users at IRC with the EVM don't have any issues with the EVM and more recent kernels.
However, we all switched to using 12V AC adaptors with the EVM, as we ALWAYS had stability issues with 5V adaptors.
I guess both you and Nikolaus are running your EVM with 5V? Then that would be a difference!
aTc found some interesting information about that:
page 19 of omap5432-ref-swcu130.pdf: if the input voltage from the jack is below approximately 5.60V, load switch U4 is enabled (driving the main 5V power rail DC_5V with the jack input), and if it is > 5.60V then load switch U18 is enabled (driving the main 5V power rail DC_5V with the SMPS 5V output).
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So that means, if you use 5V, you most probably have U4 enabled whereas everyone who runs at 12V has U18 enabled (which uses SMPS 5V output instead of direct Jack input).
It seems to be unstable when running directly from jack input. The igepv5 doesn't have that issue - so something is different here. Could it be that the power is filtered better on the igepv5?
What we've found out on the Pyra is that it runs A LOT more stable with a battery. I guess the battery provides a more stable power source than some random USB AC adaptor.
So maybe it's a hardware issue of the EVM, which runs unstable whenever rail DC_5V is powered directly from the input jack and NOT from SMPS 5V output.
It sounds like they forgot to smoothen and filter the power source here, so the better your AC adaptor is, the more stable it runs.
- 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 _______________________________________________ Kernel mailing list Kernel@pyra-handheld.com http://pyra-handheld.com/cgi-bin/mailman/listinfo/kernel