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

On Tue, Jan 3, 2012 at 3:54 PM, Bedia, Vaibhav [off-list ref] wrote:

Hi Govindraj,

On Mon, Jan 02, 2012 at 16:00:37, Govindraj wrote:

quoted

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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