From: Dexuan Cui <decui@microsoft.com>
To: "dmitry.torokhov@gmail.com" <dmitry.torokhov@gmail.com>
Cc: KY Srinivasan <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
"sashal@kernel.org" <sashal@kernel.org>,
"linux-hyperv@vger.kernel.org" <linux-hyperv@vger.kernel.org>,
"linux-input@vger.kernel.org" <linux-input@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Michael Kelley <mikelley@microsoft.com>
Subject: RE: [PATCH] Input: hyperv-keyboard: Add the support of hibernation
Date: Tue, 5 Nov 2019 05:43:04 +0000 [thread overview]
Message-ID: <PU1P153MB01699917C92952BAD6B7A1E1BF7E0@PU1P153MB0169.APCP153.PROD.OUTLOOK.COM> (raw)
In-Reply-To: <20191003174530.GB22365@dtor-ws>
> From: dmitry.torokhov@gmail.com <dmitry.torokhov@gmail.com>
> Sent: Thursday, October 3, 2019 10:46 AM
> ...
> Right. I think in practice the current suspend implementation can work
> as freeze() for the HV keyboard, because in suspend you shut off vmbus
> channel, so there should not be wakeup signals anymore. What you do not
> want is to have the current resume to be used in place of thaw(), as
> there you re-enable the vmbus channel and resume sending wakeup requests
> as you are writing out the hibernation image to storage.
>
> I think if vmbus allowed HV keyboard driver to supply empty thaw() and
> poweroff() implementations, while using suspend() as freeze() and
> resume() as restore(), it would solve the issue for you.
>
> Dmitry
BTW, IMO thaw() should not be empty, because drivers/base/power/main.c:
pm_op() uses ops->thaw for both PM_EVENT_THAW and PM_EVENT_RECOVER.
PMSG_RECOVER is the same as PM_EVENT_RECOVER.
If some step in hibernation_snapshot() -> create_image() fails, we call
dpm_resume_start(PMSG_RECOVER) at the end of create_image(), and call
dpm_resume() in hibernation_snapshot(). An empty thaw() can not bring the
device back to normal.
Thanks,
-- Dexuan
prev parent reply other threads:[~2019-11-05 5:43 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-11 23:36 [PATCH] Input: hyperv-keyboard: Add the support of hibernation Dexuan Cui
2019-09-19 16:17 ` dmitry.torokhov
2019-09-21 6:56 ` Dexuan Cui
2019-09-25 19:49 ` Dexuan Cui
2019-09-28 0:31 ` dmitry.torokhov
2019-09-30 22:09 ` Dexuan Cui
2019-09-30 23:06 ` dmitry.torokhov
2019-10-03 5:35 ` Dexuan Cui
2019-10-03 6:44 ` Dexuan Cui
2019-10-03 17:45 ` dmitry.torokhov
2019-10-03 18:18 ` Dexuan Cui
2019-11-05 5:18 ` Dexuan Cui
2019-11-05 5:43 ` Dexuan Cui [this message]
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