Rafael J. Wysocki wrote:
On Sunday, 14 of September 2008, Jeff Garzik wrote:
Tejun Heo wrote:
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.
Did these changes ever get separated out?
I only have the 'combo' patch if that's what you're asking about. [The latest
version is at http://bugzilla.kernel.org/attachment.cgi?id=17702&action=view]
Still, I can easily split the patch, although in that case the reason for the
DMI changes won't be very clear without a reference to the SATA changes IMO.
That's the nature of every single API change -- you have the change, and
then you have the users.
Respectfully, please split up the patch as requested, into DMI subsystem
and ata subsystem pieces.
Re-reviewing the patch, I would even think that you should split out the
kernel/power/disk and linux/kernel.h changes as well.
Jeff
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