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

[Jeff Garzik]

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




--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/