RE: [RFC]add ACPI hooks for IDE suspend/resume

["Li, Shaohua" <shaohua.li@intel.com>]

Hi,
>
>On 12/7/05, Shaohua Li <shaohua.li@intel.com> wrote:
>> On Wed, 2005-12-07 at 16:49 +0100, Bartlomiej Zolnierkiewicz wrote:
>> > On 12/7/05, Alan Cox <alan@lxorguk.ukuu.org.uk> wrote:
>> > > On Mer, 2005-12-07 at 15:45 +0100, Bartlomiej Zolnierkiewicz
wrote:
>> > > > OK, I understand it now - when using 'ide-generic' host driver
for
>IDE
>> > > > PCI device, resume fails (for obvious reason - IDE PCI device
is
>not
>> > > > re-configured) and this patch fixes it through using ACPI
methods.
>> >
>> > I was talking about bugzilla bug #5604.
>> Sorry for my ignorance in IDE side. From the ACPI spec, there isn't a
>> generic way to save/restore IDE's configuration. That's why ACPI
>> provides such methods. I suppose all IDE drivers need call the
methods,
>> wrong?
>
>From the hardware POV:
>* there is generic way to save/restores IDE device's configuration
>* there is no generic way to save/restore IDE controller's
configuration
>
>From the software POV what we only do currently is setting controller
>and drive for a correct transfer mode by using host driver specific
>callback
>(in case of using 'ide-generic' there is no such callback).
>
>> > > Even in the piix case some devices need it because the bios wants
to
>> > > issue commands such as password control if the laptop is set up
in
>> > > secure modes.
>> >
>> > I completely agree.  However at the moment this patch doesn't seem
>> > to issue any ATA commands (code is commented out in _GTF) so
>> > this is not a case for bugzilla bug #5604.
>> I actually tried to invoke ATA commands using IDE APIs, but can't
find
>> any available one. I'd be very happy if you can give me any hint how
to
>> do it or even you can fix it.
>
>Probably do_rw_taskfile() is the method you want to use, you also need
>to place invoking of ACPI provided ATA commands in the right place in
>the IDE PM state machine [ ide_{start,complete}_power_step() ].
>
>PS1 Please don't use taskfile_lib_get_identify(), drive->id
>should contain valid ID - if it doesn't it is a BUG.
>
>PS2 Have you seen libata ACPI patches by Randy?
>Maybe some of the code dealing with ACPI can be put to
><linux/ata.h> and be shared between IDE and libata drivers?
Thanks a lot! I'll try your suggestions after my travel. Hopefully I can
understand the IDE staffs you mentioned then :).

Thanks,
Shaohua
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