Am 20.09.2016 um 02:22 schrieb Michael Mrozek EvilDragon@openpandora.org:
Am Mon, 19 Sep 2016 12:14:04 -0400 hat Roy Gillotti gillottir@gmail.com geschrieben:
Hi Roy,
thanks for the comprehensive test! This is quite interesting!
I didn't know the EVM even has a 5V LED, but thanks to that, two things are pretty clear here:
- When the 5V LED is on (power is below 5.6V, which means it switches
to Power Jack Input), the EVM runs unstable. At least yours, mine and aTcs, from what we know. It seems Nikolaus' one is not affected (for whatever reason).
Well, I have never tested with higher voltages.
- The voltage probably drops below 5.6V when you provide 6.2V and there
is a high current draw
So the questions are:
- What has the 5V switch to do with the power supply of the OMAP5?
Nothing.
Except one thing: if there are power sinks at the USB ports which draw high current, switching might make glitches on the DC input.
But I don't see how this should affect OMAP operation.
Unless we assume that the USB stack is unstable, i.e. if connected devices behave erratically if voltage is noisy.
BTW: I have nothing connected to USB or HDMI in my tests where the EVM runs stable from 5V.
Why does it run unstable? VSys is even lower than 5V, so what's going on there?
Does the igepv5 have the same issue? If not: What's different there?
Is that a hardware bug of the EVM or a problem with the OMAP5?
I tend to think it is an EVM specific effect. Pyra does not have this switch circuit at all.
Unfortunately I have no IGEP5 circuit diagram to compare.
- Is that switch between the two modes controllable by software?
Meaning: Can we disable that the EVM switches into that special 5V mode?
No software control.
It is mainly an automatic bypass of the 5.6V - 12V -> 5V converter (because USB and HDMI need 5V). It is bypassed if input voltage is low enough.
What Kernel are you using? I've upgraded to the letux 4.8 RC5 via aTc's repo update and noticed this behavior with my bench supply capable of delivering 4A.
5.1V - Some instabilities HDMI, SATA resets and USB devices blink out. Sometimes freezes before getting to X.
5.2V - Boots up Consistently. random Freezes when using Firefox when attempting to watch a Youtube video. Sometime just HDMI blinks out occasionally.
5.3V - Seems stable running CPU intensive things. Firefox running youtube video, running 720p video in smplayer and quake 2 at once. highest current draw observed ~1.6A during spikes. Random Freeze occurs generally within 5 to 10 minutes of use.
5.4V - Same as 5.3V
5.5V - Same as 5.4V
5.6V - 5V LED blinks, HDMI blinks out or won’t go into a resolution above 1024x768. Can seem to use firefox, youtube videos without issues.
5.7V - 5V LED is off, but turns on when drawing ~1A. HDMI working appropriately.
5.8V - Same as 5.7V
5.9V - 5V LED is off, but turns on when drawing ~1A. oddly the 1024x768 bug appears again at this voltage. powered off a few times to confirm it.
6.0V - 5V LED is only displays as on with current draw is ~1.4A. Seems stable otherwise.
6.2V - 5V LED is only blinked a few times, when the current draw briefly spiked about 1.6A. seems just as stable.
6.3V - 5V LED off completely. No noticeable blinks. appears stable.
On Mon, Sep 19, 2016 at 12:06 PM, Tony Lindgren tony@atomide.com wrote:
- H. Nikolaus Schaller hns@goldelico.com [160919 02:55]:
Am 19.09.2016 um 11:39 schrieb Grazvydas Ignotas notasas@gmail.com: I could give it a try on my uEVM to add another data point. FWIW my uEVM has been always rock stable (12V supply), but I haven't updated my kernel for a while.
Yes, would be nice to compare your results and observations.
My omap5-uevm is on a 5V power supply right now it seems, I'm pretty sure it used to have 12V supply earlier.
Regards,
Tony _______________________________________________ Kernel mailing list Kernel@pyra-handheld.com http://pyra-handheld.com/cgi-bin/mailman/listinfo/kernel
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