On Thu, 2012-02-16 at 10:13 -0500, Alan Stern wrote:

On Thu, 16 Feb 2012, Zhang Rui wrote:

quoted

quoted

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