Re: [PATCH 00/11] OMAP3 CPUidle patches

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Kalle Jokiniemi <ext-kalle.jokiniemi@xxxxxxxxx> writes:

> On pe, 2008-07-04 at 15:15 +0530, ext Rajendra Nayak wrote:
> ...
>> > ext Högander Jouni <jouni.hogander@xxxxxxxxx> writes:
>
> ...
>
>> > 
>> > So Rajendra sent his uImage and it works quite ok what comes to off
>> > mode on my sdp board. I still see problems with serial console (slow)
>> > and on boot I need to generate manually interrupts to get it to
>> > boot. Otherwise board hangs at this point:
>> 
>> Yes, I noticed this as well. It takes quite long to bootup if you don't 
>> generate UART interrupts.
>> After bootup once RET/OFF is hit, it takes a few hits to come out of it
>> as IO wakeup is missing.
>
> Jouni had a theory that the ethernet device could cause this slowness
> trouble in the startup, so I investigated the matter a little further.
> By enabling the debug prints in the ethernet chip driver,
>
> diff --git a/drivers/net/smc91x.c b/drivers/net/smc91x.c
> index 776c81d..7d1eead 100644
> --- a/drivers/net/smc91x.c
> +++ b/drivers/net/smc91x.c
> @@ -62,7 +62,7 @@ static const char version[] =
>  
>  /* Debugging level */
>  #ifndef SMC_DEBUG
> -#define SMC_DEBUG              0
> +#define SMC_DEBUG              1
>  #endif
>
>
> I was able to see, that we get lots of RX overrun interrupts with
> cpu_idle, meaning that incoming stuff is not getting processed. By
> generating UART interrupts, I we probably can also catch more network RX
> interrupts and this helps the bootup go faster. With cpu_idle disabled,
> there were no RX overruns.

Your investigation supports this theory. Interrupt line from eth chip
doesn't wake up mpu. I assume it is gpio line. Those are added to mpu
wake-up events group, gpio wake-ups are enabled and mpu peripherals
group wake-up event interrupt is enabled.

I'm suspecting that this problem happens if state where mpu is in
sleep state and core+per are awake is used.

Any comments from TI people what might be wrong?

>
> I'll try to see if this can be fixed somehow.
>
>> 
>> > 
>> > eth0: link up
>> > Sending DHCP requests ., OK
>> > IP-Config: Got DHCP answer from 0.0.0.0, my address is 192.168.2.101
>> > IP-Config: Complete:
>> >      device=eth0, addr=192.168.2.101, mask=255.255.255.0, 
>> > gw=192.168.2.1,
>> >      host=192.168.2.101, domain=ntc.nokia.com, nis-domain=(none),
>> >      bootserver=0.0.0.0, rootserver=172.22.146.197, rootpath=
>> > Looking up port of RPC 100003/2 on 172.22.146.197
>> > Looking up port of RPC 100005/1 on 172.22.146.197
>> > VFS: Mounted root (nfs filesystem).
>> > Freeing init memory: 108K
>> > 
>> > Rajendra, are you still using .config file you sent to me? Are all the
>> > changes in your tree available in l-o list.
>> 
>> Yes, all the changes are part of the 11 patch set + 1 rework fixes patch I sent.
>> To debug further, can you put a few prints in omap3_enter_idle and omap3_enter_idle_bm
>> to see what states are selected by the menu gov. 
>> We will then know if CORE RET/OFF is attempted but not achieved due to some reason, or 
>> never attempted altogether.
>
> My setup does not seem to go beyond C2 state, btw. So I'll need to debug
> that also a bit. The above-mentioned patches are applied.
>
> Br, Kalle
>
>
> ...
>
>
>

-- 
Jouni Högander

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