Re: [PATCH] SATA: Blacklist systems that spin off disks during ACPIpower off

[Tejun Heo]

Rafael J. Wysocki wrote:
> SATA: Blacklist systems that spin off disks during ACPI power off
> 
> Some notebooks from HP have the problem that their BIOSes attempt to
> spin down hard drives before entering ACPI system states S4 and S5.
> This leads to a yo-yo effect during system power-off shutdown and the
> last phase of hibernation when the disk is first spun down by the
> kernel and then almost immediately turned on and off by the BIOS.
> This, in turn, may result in shortening the disk's life times.
> 
> To prevent this from happening we can blacklist the affected systems
> using DMI information.  However, only the on-board controlles should
> be blacklisted and their PCI slot numbers can be used for this
> purpose.  Unfortunately the existing interface for checking DMI
> information of the system is not very convenient for this purpose,
> because to use it, we would have to define special callback functions
> or create a separate struct dmi_system_id table for each blacklisted
> system.
> 
> To overcome this difficulty introduce a new function
> dmi_first_match() returning a pointer to the first entry in an array
> of struct dmi_system_id elements that matches the system DMI
> information.  Then, we can use this pointer to access the entry's
> .driver_data field containing the additional information, such as
> the PCI slot number, allowing us to do the desired blacklisting.
> 
> Introduce a new libata flag ATA_FLAG_NO_POWEROFF_SPINDOWN that, if
> set, will prevent disks from being spun off during system power off
> and hibernation (to handle the hibernation case we need a new system
> state SYSTEM_HIBERNATE_ENTER that can be checked against by libata,
> in analogy with SYSTEM_POWER_OFF).  Use dmi_first_match() to set this
> flag for some systems affected by the problem described above (HP nx6325,
> HP nx6310, HP 2510p).
> 
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>

libata part looks good to me but I think it would be better to
separate out DMI changes into a separate patch.

Thanks.

-- 
tejun
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