[PATCH] powerpc: Revert support for ibm,drc-info devtree property

Subsystems: linux for powerpc (32-bit and 64-bit), the rest

STALE3088d

2 messages, 2 authors, 2018-02-23 · open the first message on its own page

[PATCH] powerpc: Revert support for ibm,drc-info devtree property

From: Michael Bringmann <hidden>
Date: 2018-02-13 20:03:40

This reverts commit 02ef6dd8109b581343ebeb1c4c973513682535d6.

The earlier patch tried to enable support for a new property
"ibm,drc-info" on powerpc systems.

Unfortunately, some errors in the associated patch set break things
in some of the DLPAR operations.  In particular when attempting to
hot-add a new CPU or set of CPUs, the original patch failed to
properly calculate the available resources, and aborted the operation.
In addition, the original set missed several opportunities to compress
and reuse common code.

As the associated patch set was meant to provide an optimization of
storage and performance of a set of device-tree properties for future
systems with large amounts of resources, reverting just restores
the previous behavior for existing systems.  It seems unnecessary
to enable this feature and introduce the consequent problems in the
field that it will cause at this time, so please revert it for now
until testing of the corrections are finished properly.

Signed-off-by: Michael W. Bringmann <redacted>
---
 arch/powerpc/kernel/prom_init.c     | 1 +
 1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index adf044d..d22c41c 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -874,7 +874,7 @@ struct ibm_arch_vec __cacheline_aligned ibm_architecture_vec = {
 		.mmu = 0,
 		.hash_ext = 0,
 		.radix_ext = 0,
-		.byte22 = OV5_FEAT(OV5_DRC_INFO),
+		.byte22 = 0,
 	},
 
 	/* option vector 6: IBM PAPR hints */

Re: powerpc: Revert support for ibm,drc-info devtree property

From: Michael Ellerman <hidden>
Date: 2018-02-23 05:39:20

On Tue, 2018-02-13 at 20:02:53 UTC, Michael Bringmann wrote:
This reverts commit 02ef6dd8109b581343ebeb1c4c973513682535d6.

The earlier patch tried to enable support for a new property
"ibm,drc-info" on powerpc systems.

Unfortunately, some errors in the associated patch set break things
in some of the DLPAR operations.  In particular when attempting to
hot-add a new CPU or set of CPUs, the original patch failed to
properly calculate the available resources, and aborted the operation.
In addition, the original set missed several opportunities to compress
and reuse common code.

As the associated patch set was meant to provide an optimization of
storage and performance of a set of device-tree properties for future
systems with large amounts of resources, reverting just restores
the previous behavior for existing systems.  It seems unnecessary
to enable this feature and introduce the consequent problems in the
field that it will cause at this time, so please revert it for now
until testing of the corrections are finished properly.

Signed-off-by: Michael W. Bringmann <redacted>
Applied to powerpc fixes, thanks.

https://git.kernel.org/powerpc/c/c7a3275e0f9e461bb8942132aa6914

cheers
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