On 05/05/2014 03:21 PM, Alexander Graf wrote:

On 05/05/2014 02:17 PM, Tudor Laurentiu wrote:

quoted

On 04/30/2014 11:09 PM, Alexander Graf wrote:

quoted

On 30.04.14 22:03, Stuart Yoder wrote:

quoted

quoted

-----Original Message-----
From: Alexander Graf [mailto:agraf@suse.de]
Sent: Wednesday, April 30, 2014 2:56 PM
To: Yoder Stuart-B08248; benh@kernel.crashing.org; Wood Scott-B07421
Cc: linuxppc-dev@lists.ozlabs.org
Subject: Re: [PATCH] powerpc: move epapr paravirt init of
power_save to
an initcall


On 30.04.14 21:54, Stuart Yoder wrote:

quoted

From: Stuart Yoder <redacted>

some restructuring of epapr paravirt init resulted in
ppc_md.power_save being set, and then overwritten to
NULL during machine_init.  This patch splits the
initialization of ppc_md.power_save out into a postcore
init call.

Signed-off-by: Stuart Yoder <redacted>
---
   arch/powerpc/kernel/epapr_paravirt.c |   25
++++++++++++++++++++-----
   1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/epapr_paravirt.c

b/arch/powerpc/kernel/epapr_paravirt.c

quoted

index 6300c13..c49b69c 100644

--- a/arch/powerpc/kernel/epapr_paravirt.c
+++ b/arch/powerpc/kernel/epapr_paravirt.c

@@ -52,11 +52,6 @@ static int __init

early_init_dt_scan_epapr(unsigned

long node,

quoted

   #endif
       }

-#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
-    if (of_get_flat_dt_prop(node, "has-idle", NULL))
-        ppc_md.power_save = epapr_ev_idle;
-#endif
-
       epapr_paravirt_enabled = true;

       return 1;

@@ -69,3 +64,23 @@ int __init epapr_paravirt_early_init(void)
       return 0;
   }

+static int __init epapr_idle_init_dt_scan(unsigned long node,
+                       const char *uname,
+                       int depth, void *data)
+{
+#if !defined(CONFIG_64BIT) || defined(CONFIG_PPC_BOOK3E_64)
+    if (of_get_flat_dt_prop(node, "has-idle", NULL))
+        ppc_md.power_save = epapr_ev_idle;
+#endif
+    return 0;
+}
+
+static int __init epapr_idle_init(void)
+{
+    if (epapr_paravirt_enabled)
+        of_scan_flat_dt(epapr_idle_init_dt_scan, NULL);

Doesn't this scan all nodes? We only want to match on
/hypervisor/has-idle, no?

I cut/pasted from  the approach the existing code in that file
took, but yes you're right we just need the one property.
Let me respin that to look at the hypervisor node only.

Yeah, the same commit that introduced the breakage on has-idle also
removed the explicit check for /hypervisor.

Laurentiu, was this change on purpose?

Alex,

IIRC, at that time i had to switch from the normal "of" functions to a
completely different api that's available in early init stage. This
early "of" api is pretty limited (e.g. doesn't have a way to address a
specific node) and i had to use that function that scans the whole tree.

Ok, so it is an accident. Could you please post a patch that checks that
the node we're looking at is called "hypervisor"? The simple API should
give you enough information for that at least. Maybe you could even
check that the parent node is the root node.

Just had a quick look and it looks that that early fdt api was improved 
with a function that allows specifying a starting path for the scan 
(of_scan_flat_dt_by_path() added in commit 
57d74bcf3072b65bde5aa540cedc976a75c48e5c). So i think we can simply use 
that instead.

---
Best Regards, Laurentiu