This patch removes the driver distinction between control method (CM)
and fixed hardware (FF) buttons.  We previously needed that so we
could install either a fixed event handler or a notify handler, but
the Linux/ACPI code now handles that for us, so we don't need to
worry about it.

Note that this removes the FF/CM annotation from the "info" files
in /proc.  For example,

    /proc/acpi/button/PWRF/info:
    -type:		Power Button (FF)
    +type:		Power Button

I don't think there's anything meaningful user-space can do by
knowing whether a button is a control method or a fixed hardware
button, so nobody should be looking at the FF/CM.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

We no longer need a pointer from struct acpi_button back to the
struct acpi_device.  Everywhere we used that pointer, we either
already have, or can easily get, the acpi_device pointer without
using the copy from acpi_button.  So this patch removes the
structure element.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

This patch adds temporaries to cache the acpi_device_hid(),
acpi_device_name(), and acpi_device_class() pointers so we
don't have to clutter the code with so many uses of those
interfaces.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

It's typical and slightly more compact to look up the driver_data
structure by initializing the automatic variable at its definition.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Better to oops and learn about a bug than to silently cover it up.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

This patch changes a bit of whitespace to follow Linux conventions.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Signed-off-by: Len Brown <len.brown@intel.com>

This patch adds a .notify() method.  The presence of .notify() causes
Linux/ACPI to manage event handlers and notify handlers on our behalf,
so we don't have to install and remove them ourselves.

Note that events from fixed hardware buttons now show up as a special
notify event, so to preserve user-space backward compatibility, we
convert that back to ACPI_BUTTON_NOTIFY_STATUS.

Signed-off-by: Bjorn Helgaas <bjorn.helgaas@hp.com>
Reviewed-by: Alex Chiang <achiang@hp.com>
CC: Alexey Starikovskiy <alexey.y.starikovskiy@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

Setting ->owner as done currently (pde->owner = THIS_MODULE) is racy
as correctly noted at bug #12454. Someone can lookup entry with NULL
->owner, thus not pinning enything, and release it later resulting
in module refcount underflow.

We can keep ->owner and supply it at registration time like ->proc_fops
and ->data.

But this leaves ->owner as easy-manipulative field (just one C assignment)
and somebody will forget to unpin previous/pin current module when
switching ->owner. ->proc_fops is declared as "const" which should give
some thoughts.

->read_proc/->write_proc were just fixed to not require ->owner for
protection.

rmmod'ed directories will be empty and return "." and ".." -- no harm.
And directories with tricky enough readdir and lookup shouldn't be modular.
We definitely don't want such modular code.

Removing ->owner will also make PDE smaller.

So, let's nuke it.

Kudos to Jeff Layton for reminding about this, let's say, oversight.

http://bugzilla.kernel.org/show_bug.cgi?id=12454

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>

Disabling gpe might interfere with gpe detection/handling,
thus producing "interrupt not handled" errors.
Ironically, disabling of GPE from interrupt context is already
under spinlock, so only userspace needs to start using it.

Signed-off-by: Alexey Starikovskiy <astarikovskiy@suse.de>
Signed-off-by: Len Brown <len.brown@intel.com>