Re: [PATCH v2] hid: enable hid device to suspend/resume asynchronously

From: Fu, Zhonghui
Date: Mon Nov 23 2015 - 01:03:40 EST

On 11/16/2015 11:26 PM, Jiri Kosina wrote:
> On Mon, 16 Nov 2015, Fu, Zhonghui wrote:
>> Hi Jiri,
>> Any comments about this patch?
>> After enabling the HID devices suspend/resume asynchronously on ASUS
>> T100TA(Baytrail-T platform), the system suspend-to-idle/resume time is
>> reduced about 20ms. Although this improvement is not very significant.
>> But, if the suspend/resume operation of HID devices is very
>> time-consuming on some other platforms, this patch can improve
>> significantly system suspend/resume speed on these platforms.
> Hi,
> I don't think the question I've raised at
> has ever been answered or at least discussed ... ?
Sorry for missing this mail.

At present, the file(/sys/.../power/async) can be used to enable one device suspend/resume asynchronously. My patch only changes the default value of this file from "disabled" to "enabled".
The sole difference of asynchronous suspend/resume mode is that the suspend/resume operation of one device is carried out in a separate kernel thread, and PM core ensures all related dependency. I have verified this patch on some platforms, such as ASUS T100TA. Actually, many other devices have used this feature for a long time.


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