Re: [stable] [PATCH] PNPACPI: Enable PNPACPI _PSx Support, v3

[Greg KH <greg@kroah.com>]

On Thu, Apr 02, 2009 at 03:10:36PM +0200, Thomas Renninger wrote:
> Hi,
> 
> I remember a bug (serial device not working)
> related to serial and docking on Lenovo.
> I wonder whether this could be related to this fix.
> 
> This one also looks worth adding to stable kernel, at least
> after 2.6.30 does not show regressions for a while.
> 
> On Monday 30 March 2009 19:31:06 Witold Szczeponik wrote:
> > Subject: Enable PNPACPI _PSx Support, v3
> > 
> > 
> > (This is an update to the patch presented earlier in
> > http://lkml.org/lkml/2008/12/8/284, with new error handling.)
> > 
> > This patch sets the power of PnP ACPI devices to D0 when they
> > are activated and to D3 when they are disabled.  The latter is
> > in correspondence with the ACPI 3.0 specification, whereas the
> > former is added in order to be able to power up a device after
> > it has been previously disabled (or when booting up a system).
> > (As a consequence, the patch makes the PnP ACPI code more ACPI
> > compliant.)
> > 
> > Section 6.2.2 of the ACPI Specification (at least versions 1.0b
> > and 3.0a) states: "Prior to running this control method [_DIS],
> > the OS[PM] will have already put the device in the D3 state."
> > Unfortunately, there is no clear statement as to when to put
> > a device in the D0 state. :-( Therefore, the patch executes the
> > method calls as _PS3/_DIS and _SRS/_PS0. What is clear: "If the
> > device is disabled, _SRS enables the device at the specified
> > resources." (From the ACPI 3.0a Specification.)
> > 
> > The patch fixes a problem with some IBM ThinkPads (at least the
> > 600E and the 600X) where the serial ports have a dedicated
> > power source that needs to be brought up before the serial port
> > can be used.  Without this patch, the serial port is enabled
> > but has no power. (In the past, the tpctl utility had to be
> > utilized to turn on the power, but support for this feature
> > stopped with version 5.9 as it did not support the more recent
> > kernel versions.)
> > 
> > The error handlers that handle any errors that can occur during
> > the power up/power down phases return the error codes to the
> > caller directly.  Comments welcome! :-)
> > 
> > No regressions were observed on hardware that does not require
> > this patch.
> > 
> > The patch is applied against 2.6.27.x.
> > 
> > 
> > Signed-off-by: Witold Szczeponik <Witold.Szczeponik@gmx.net>
> CC: stable@kernel.org
> ...

What specific git commit id in Linus's tree is this?

thanks,

greg k-h