topic Re: Recovery time for Linux from STOP or LPSTOP3 mode in Vybrid Processors

Recovery time for Linux from STOP or LPSTOP3 mode

Larry5335 — Mon, 28 Oct 2013 18:21:41 GMT

When the A5 core is in STOP mode running the Linux BSP, how long does it take before Linux will respond to new tasks? How long if using LPSTOP3 mode?

Re: Recovery time for Linux from STOP or LPSTOP3 mode

karina_valencia — Mon, 28 Oct 2013 22:56:12 GMT

timesyssupport can you help on this case?

Re: Recovery time for Linux from STOP or LPSTOP3 mode

timesyssupport — Wed, 30 Oct 2013 22:19:12 GMT

Hello Larry,

I wanted to let you know that we are currently investigating this issue. I will let you know when we have an update available.

Thanks,

Timesys Support

Re: Recovery time for Linux from STOP or LPSTOP3 mode

karina_valencia — Tue, 05 Nov 2013 18:36:11 GMT

timesyssupport do you have an advance on this case?

Re: Recovery time for Linux from STOP or LPSTOP3 mode

timesyssupport — Tue, 05 Nov 2013 21:11:49 GMT

Hello Larry,

Linux can be put into a LOW POWER STOP mode on Vybrid by issuing the command 'echo -n "mem" > /sys/power/state' on a terminal. We have found that resuming from this mode typically takes 270-300ms as reported by Linux, using an NFS mounted RFS and with an SD card inserted. (The millesecond number reported by either 'early resume' or 'resume' appears to be appended by '1206', eg, 1206270 ms, but this is not correct, as that would equate to ~20 minutes, and the device comes up in less than a second).

The current Linux BSP does not have support for LPSTOPx modes. We can review the support for these modes for the next major Linux kernel update for Vybrid (scheduled for end of Q4).

Thanks,

Timesys Support