Re: [PATCH v2] Add suspend/resume for HPET

On Thu, 2007-03-29 at 15:46 +0200, Maxim Levitsky wrote:
Subject: Add suspend/resume for HPET
This adds support of suspend/resume on i386 for HPET
Signed-off-by: Maxim Levitsky <maximlevitsky@xxxxxxxxx>

+static struct sysdev_class hpet_class = {
+ set_kset_name("hpet"),
+ .suspend = hpet_suspend,
+ .resume = hpet_resume,
+};
+
+static struct sys_device hpet_device = {
+ .id = 0,
+ .cls = &hpet_class,
+};

Sorry for being inresponsive. I was travelling and unexpectedly cut off
from the internet for some days.

While I agree in principle with the patch, I'm a bit uncomfortable. The
sys device suspend / resume ordering is not guaranteed and relies on the
registering order.

Jeff still seems to have problems with CONFIG_NO_HZ=n and it might be
caused by time keeping / tick management resume happening before the
HPET resume.

The required resume order is:

clocksources
timekeeping
clockevents
tick management

I'm not sure how to do this properly with the sys device facilities, but
I look into it.

/me goes off to understand the sys device magic.

tglx


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