Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1756292Ab2BQBML (ORCPT <rfc822;w@1wt.eu>);
	Thu, 16 Feb 2012 20:12:11 -0500
Received: from mga02.intel.com ([134.134.136.20]:46113 "EHLO mga02.intel.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1754860Ab2BQBMJ (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Thu, 16 Feb 2012 20:12:09 -0500
X-ExtLoop1: 1
X-IronPort-AV: E=Sophos;i="4.67,352,1309762800"; 
   d="scan'208";a="108972769"
Subject: Re: [RFC PATCH 2/6] ACPI: Reference devices in ACPI Power Resource
From: Lin Ming <ming.m.lin@intel.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Zhang Rui <rui.zhang@intel.com>, "Rafael J. Wysocki" <rjw@sisk.pl>,
        Jeff Garzik <jgarzik@pobox.com>, Tejun Heo <tj@kernel.org>,
        Len Brown <lenb@kernel.org>, linux-kernel@vger.kernel.org,
        linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org,
        linux-pm@vger.kernel.org
In-Reply-To: <Pine.LNX.4.44L0.1202161010500.1268-100000@iolanthe.rowland.org>
References: <Pine.LNX.4.44L0.1202161010500.1268-100000@iolanthe.rowland.org>
Content-Type: text/plain; charset="UTF-8"
Date: Fri, 17 Feb 2012 09:12:06 +0800
Message-ID: <1329441126.3376.30.camel@minggr>
Mime-Version: 1.0
X-Mailer: Evolution 2.30.3 
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org
Content-Length: 2647
Lines: 81

On Thu, 2012-02-16 at 10:13 -0500, Alan Stern wrote:
> On Thu, 16 Feb 2012, Zhang Rui wrote:
> 
> > > I'm not exactly sure what you're trying to achieve and what you mean by
> > > "resume a device directly"?  Do you want to run the device's resume
> > > callback at the time when another device is being resumed?
> > > 
> > I mean, wakeup event is sent to ATA port, but our goal is to resume
> > ZPODD after receiving this wakeup event.
> > Ideally, it is ACPI that resumes ATA port. And then, the ATA port
> > runtime resumes ZPODD. But this does not look good to runtime resume a
> > child device in the parent's .runtime_resume callback.
> > So I introduced these two APIs so that an runtime_resume request can be
> > sent to ZPODD directly and the runtime PM core can resume all the
> > parents of ZPODD automatically.
> 
> It's not clear what you're trying to achieve.  Do you basically want
> the ZPODD always to be suspended and resumed along with the ATA port,
> or should it be possible to suspend the ZPODD while the port remains
> running?

We want to ZPODD always to be suspended and resumed along with the ATA
port.

Below is part of the GPE handler for ZPODD device attention event.

        Scope (\_GPE)
        {
            Method (_L13, 0, NotSerialized)
            {
                ADBG ("ZPODD DA Event")
                ....

                Notify (\_SB.PCI0.SAT0.PRT2, 0x02)
                ....
            }
        }

It maybe a bit confused, but actually, \_SB.PCI0.SAT0.PRT2 is bind to
the attached device, not the ata port itself.

See below commit in linux-next tree.
75d22c(libata: Bind the Linux device tree to the ACPI device tree)

And below notify handler(PATCH 6) will resume the attached device(CDROM
in ZPODD case).

+static void ata_acpi_wake_dev(acpi_handle handle, u32 event, void *context)
+{
+       struct ata_device *ata_dev = context;
+
+       if (event == ACPI_NOTIFY_DEVICE_WAKE && ata_dev)
+               scsi_autopm_get_device(ata_dev->sdev);
+}
+

But the code to power on/power off the device is in ata_acpi_set_state,
which is called when ata port is resumed/suspended.

ata_eh_handle_port_resume/suspend
    ata_acpi_set_state
        ata_for_each_dev {
            acpi_bus_set_power(<the acpi handle of the device>, acpi_state)
        }

Could you take a look at PATCH 6?
It's more clear over there.

Thanks,
Lin Ming

> 
> Alan Stern
> 


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/