2011/4/12 Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
On Tue, 12 Apr 2011, Jiejing.Zhang wrote:Bear in mind that rotating disk drives typically take several hundred
> Hi,
>
> Does anyone have comments on this driver?
>
> Best regards,
> Zhang Jiejing
>
>
> 2011/4/7 Jiejing Zhang <kzjeef@xxxxxxxxx>
>
> > From: Zhang Jiejing <jiejing.zhang@xxxxxxxxxxxxx>
> >
> > This patch add function to check each device's suspend time
> > consumption. If any driver takes more time that the threshold (default
> > 0.5 ms), it will print a warnning message including the device and bus
> > name on the console. You can change the threshold on-the-fly by
> > modify file '/sys/power/device_suspend_time_threshold' to adjust this
> > value,the unit is in microsecond.
milliseconds to spin down. The warning would always trigger. That
doesn't seem particularly useful.
I think it's better change the default value 0 to disable it, enable it only some one write a threshold.
First of all, it's a debug function (depends on PM_DEBUG), It's useful in embedded area, like mobile phone or e-book, they are suspend/resume very frequently and required resume as quick as possible. This debug function can used to figure out which driver(s) is/are slow on suspend/resume.
I fact that embedded engineer meets a lot is, after some development the total time of suspend/resume is become slow, since there was a lot driver may affect the total time, it's function can help them to figure out which driver is slow, and it's make life easier.
Thanks.
Jiejing Zhang
Alan Stern
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