Re: [PATCH v8 19/20] OMAP2+: UART: Do not gate uart clocks if used for debug_prints

[Govindraj <govindraj.ti@gmail.com>]

On Tue, Jan 3, 2012 at 3:54 PM, Bedia, Vaibhav <vaibhav.bedia@ti.com> wrote:
> Hi Govindraj,
>
> On Mon, Jan 02, 2012 at 16:00:37, Govindraj wrote:
>>
>> currently runtime pm is available from omap-serial device and not from tty_dev.
>> Setting tty_dev wakeup is to use irq_wakeup from suspend available
>> from serail_core layer which I think we are not using for omap-uart
>> and we use pad wakeup from suspend path.
>>
>> Also omap-uart.x/power/wakeup is used to gate uart clocks using runtime
>> PM api's in omap-serial driver.
>>
>
> Thanks for clarifying. On AM335x, one of the UARTs is in a wakeup domain
> and swakeup from this is used to come out of suspend.
>
> I have basic suspend-resume working on it. Strangely this works irrespective
> of the value of tty_dev wakeup entry. Do you know if this is expected on OMAP?
>

AFAIK yes.

> The other issue concerning runtime PM is that as soon as I set a non-zero to
> the autosuspend_delay_ms I get some garbage characters and eventually the
> console stops responding.
>
> [root@arago /]# cat .../omap_uart.0/power/autosuspend_delay_ms
> -1
> [root@arago /]# echo 3000 > ÖKWëé«+×é«+wU.Éѹ,z,½Ý.ɽosuspend_delayÕ£½ÍÕÍ...
> [root@arago /]# <- No response after some time
>

try enabling CONFIG_CPU_IDLE for pm qos_usage from uart driver.

--
Thanks,
Govindraj.R
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