Comment 8 for bug 508847

Finally figured what magic quoting to give grub.

acpi_osi='"!Windows 2009"'

restores the working behaviour of the Fn+F4 key combo.

DAMNIT HP!!

This should be possible to patch around in the Kernel, adding the appropriate DMI information to drivers/acpi/blacklist.c

Something like

 {
 .callback = dmi_disable_osi_win7,
 .ident = "HP 6730b",
 .matches = {
       DMI_MATCH(DMI_SYS_VENDOR, "Hewlett-Packard"),
       DMI_MATCH(DMI_PRODUCT_NAME, "HP Compaq 6730b (KU216ET#ABU)"),
  },
 },

Might do the trick (I've not tested it since rebuilding the whole kernel is tedious!)

Perhaps a more generic match might be possible.

Other alternatives include investigating the DSDT to try and determine which magic location storing the OSI value in causes the firmware to break the FN+F4 combo, and write a driver to poke it back.

ACPI fails so damned badly because of the _OSI call, it should _never_ have been allowed in the first place. (Microsoft should release updates to fix their bugs!)

So, now I'm in the happy situation of having all the other Windows 7 specific API fixes being un-available on my machine because HP chose to break with the ACPI _standard_ with regards handling of the video hotkey. (Similarly to how they ignored it for the brightness keys).

VERY Unimpressed HP.