From: Michael Neuling <mikey@neuling.org>
Date: Mon, 13 May 2019 05:39:10 +0000 (+1000)
Subject: powerpc: Document xive=off option
X-Git-Tag: v5.3-rc1~94^2~130
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=ba45cff610a4223ce3ad98a700a820e3d60e3f7c;p=thirdparty%2Flinux.git

powerpc: Document xive=off option

commit 243e25112d06 ("powerpc/xive: Native exploitation of the XIVE
interrupt controller") added an option to turn off Linux native XIVE
usage via the xive=off kernel command line option.

This documents this option.

Signed-off-by: Michael Neuling <mikey@neuling.org>
Reviewed-by: Cédric Le Goater <clg@kaod.org>
Acked-by: Stewart Smith <stewart@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index a4c3538857e93..7b15abf7db213 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5272,6 +5272,15 @@
 			Format:
 			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
 
+	xive=		[PPC]
+			By default on POWER9 and above, the kernel will
+			natively use the XIVE interrupt controller. This option
+			allows the fallback firmware mode to be used:
+
+			off       Fallback to firmware control of XIVE interrupt
+				  controller on both pseries and powernv
+				  platforms. Only useful on POWER9 and above.
+
 	xhci-hcd.quirks		[USB,KNL]
 			A hex value specifying bitmask with supplemental xhci
 			host controller quirks. Meaning of each bit can be