Re: OMAP3 PM: off-mode during idle, problem with UART1 console

[Kevin Hilman <khilman@deeprootsystems.com>]

"Nayak, Rajendra" <rnayak@ti.com> writes:

> What Silicon Rev does your SDP have? I currently am using an ES3.1 based SDP
> and I havent seen any of these issues you have reported with off-while-idle.

I have and ES3.0 SDP. 

> Infact I have kept the board running overnight a couple times in the last week 
> with off-while-idle and voltage scaling to 0v enabled, mainly to test the recent
> patch set (disabling Auto idle for PER in scratchpad memory) for stability.

Ah, great.  That is really good to know.  Are you using omap_3430sdp_pm_defconfig?

I see the same problems with and without your patches.

> I will see if I can get hold of an ES3 and ES2.1 based SDP's and see if I reproduce
> the issue. Besides I use nfs and I am not sure if that's got something to do with it.
> Will try a ramdisk also.

I'm using a ramdisk.

> Does it take you a while to reproduce this, or is it seen after the very first UART
> inactivity?

It happens on the first try.

Could you try my uImage which has my initramfs rootfs built-in on your
ES3.1 SDP?

   http://userweb.kernel.org/~khilman/tmp/rajendra/uImage.pm-vanilla

Immediately after booting, I do

# echo 1 > /sys/power/enable_off_mode                                           
# echo 1 > /sys/power/voltage_off_while_idle                                    
# echo 1 > /sys/power/sleep_while_idle                                          

and after UART inactivity, I start to see sys_off_mode LED blinking.

Kevin


>>-----Original Message-----
>>From: linux-omap-owner@vger.kernel.org 
>>[mailto:linux-omap-owner@vger.kernel.org] On Behalf Of Kevin Hilman
>>Sent: Wednesday, June 17, 2009 2:35 AM
>>To: Nayak, Rajendra; Woodruff, Richard
>>Cc: linux-omap@vger.kernel.org
>>Subject: OMAP3 PM: off-mode during idle, problem with UART1 console
>>
>>Rajendra, Richard,
>>
>>Hoping you can shed some light, or give me some direction on where to
>>debug this further...
>>
>>With the latest PM branch, I've notice that off-while idle isn't
>>working on the SDP, but the same kernel works fine on the RX51.
>>RET-while-idle works fine on both.  This is with CPUidle disabled, so
>>just using the default idle where MPU and CORE are changed together.
>>
>>More specifically, it seems to be the UART1 (CORE) console that never
>>comes back from off-while-idle, but the UART3 (PER) console on RX51
>>works.
>>
>>On SDP, if I
>>
>># echo 1 > /sys/power/enable_off_mode
>># echo 1 > /sys/power/voltage_off_while_idle
>># echo 1 > /sys/power/sleep_while_idle
>>
>>After the UART inactivty timeout of 5 seconds, I start to see the
>>sys_off_mode LED toggling between red and green with system timer
>>wakeups.
>>
>>If I then push a key on the UART1 console, the LED goes green, stays
>>for the 5 second UART inactivity and then goes back to toggling
>>red/green again.  However, I never get my console back and never see
>>the characters on my console.
>>
>>If I keep typing, I keep the system from going back off (based on
>>sys_off_mode LED) and as soon as I stop typing long enough for the
>>inactivity timer to expiere (5 seconds) it goes back into off.
>>
>>Any ideas what's going on here?
>>
>>On RX51, the same thing works using UART3.
>>
>>Kevin
>>
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