Fix ACPI documentation in kernel-parameters.txt

Add hint that acpi=off doesn't work on IA64.

---
 Documentation/kernel-parameters.txt |    1 +
 1 file changed, 1 insertion(+)

Index: b/Documentation/kernel-parameters.txt
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@@ -135,6 +135,7 @@ and is between 256 and 4096 characters. 
 				strictly ACPI specification compliant.
 
 			See also Documentation/pm.txt, pci=noacpi
+			On IA64, ACPI cannot be deactivated.
 
 	acpi_sleep=	[HW,ACPI] Sleep options
 			Format: { s3_bios, s3_mode }

Would it make sense to add code to detect this and print a kernel message like

warning: ACPI is always enabled on IA64; ignoring "acpi=off"

No one reads documentation :)

- R.

Hello,

The idea is not bad, but it should not make sense to have it only for ACPI and not for other arch-specific options ...

Regards
Bernhard