Hi,

chunfeng yun [off-list ref] writes:

On Tue, 2016-05-03 at 12:33 +0300, Felipe Balbi wrote:

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Hi,

chunfeng yun [off-list ref] writes:

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chunfeng yun [off-list ref] writes:

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On Thu, 2016-04-21 at 10:04 +0800, Chunfeng Yun wrote:

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Click mouse after xhci suspend completion but before system suspend
completion, system will not be waken up by mouse if the duration of
them is larger than 20ms which is the device UFP's resume signaling

what is "them" here ? The duration of what is longer than 20ms ?

They are "xhci suspend completion" and "system suspend completion";

It's time duration

okay. So if xhci suspend takes longer than 20ms your SPM doesn't see a
wakeup ?

It is not the time of xhci suspend consumed, but is the time of duration
from xhci suspend completion to system suspend completion(after BOOT-CPU
is turned off, SPM will be enabled to receive wakeup event)

Okay, so SPM will be the entity actually handling wakeups, right ? I'm
assuming something like this happens:

echo mem > /sys/power/state
 /* start suspending devices */
  xhci_suspend()
 /* all devices suspended */
 enable_spm()

so, if a mouse button is pressed after xhci_suspend() returns but before
enable_spm() runs, then we're gonna miss that event, am I right ?

I can't think of any way to sort this out. Let's ask on linux-pm (I've
added linux-pm to Cc list)

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lasted. Another reason is that the SPM is not enabled before system

what's SPM ?

It is System Power Management which is powered off when system is
running in normal mode, and is powered on when system enters suspend
mode. It is used to wakeup system when some wakeup sources, such as
bluetooth or powerkey etc, tigger wakeup event.

okay, thanks

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suspend compeltion, this causes SPM also not notice the resume signal.

           ^^^^^^^^^^
           completion

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So in order to reduce the duration less than 20ms, make use of
syscore's suspend/resume interface.

no, this is the wrong approach

But it seems only one workable approach from software side

I wouldn't say that. It seems to me SPM should be enabled earlier.

Yes, but normally SPM should be enabled after all CPUS are turned off,
so it's difficult to do that, I mean enable SPM before turning off CPUS

is it a requirement that SPM should be enabled only after all CPUs are
turned off ? If that's the case, then any device in the system might
have missed wakeups. This doesn't seem like a good design to me; unless
I'm missing something...

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Because the syscore runs on irq disabled context, and xhci's
suspend/resume calls some sleeping functions, enable local irq
and then disable it during suspend/resume. This may be not a problem,
since only boot CPU is runing.

another problem :) calling local_irq_{enable,disable}() is an indication
that something's wrong.

Oh!

BTW: There will be warning logs if they are not called.

yeah, I got that :-) But it's still wrong to use
local_irq_{enable,disable}() the way you're using them :-)

Yes

Thank you very much.

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-- 
balbi