Re: [Qemu-devel] [PATCH 2/2] Add PIIX4 properties to control PM system states.

[Andreas Färber]

Am 23.05.2012 15:27, schrieb Anthony Liguori:
> On 05/20/2012 04:02 AM, Gleb Natapov wrote:
>> This patch adds two things. First it allows QEMU to distinguish between
>> regular powerdown and S4 powerdown. Later separate QMP notification will
>> be added for S4 powerdown. Second it allows S3/S4 states to be disabled
>> from QEMU command line. Some guests known to be broken with regards to
>> power management, but allow to use it anyway. Using new properties
>> management will be able to disable S3/S4 for such guests.
>>
>> Supported system state are passed to a firmware using new fw_cfg file.
>> The file contains  6 byte array. Each byte represents one system
>> state. If byte at offset X has its MSB set it means that system state
>> X is supported and to enter it guest should use the value from lowest 3
>> bits.
>>
>> Signed-off-by: Gleb Natapov<address@hidden>
> 
> I see nothing wrong in principle here except that you should use a PTR
> property to pass the fw_cfg object to the ACPI PM device.

Paolo was on a quest to eliminate the PTR properties so I don't think we
should advocate adding any more. Without having reviewed the code, I
would suggest to rather QOM'ify the fw_cfg object and to use a link<>
property if needed.

Andreas

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