Re: [PATCH v3 12/17] ARM64: ACPI: Check if it runs on Xen to enable or disable ACPI

From: Hanjun Guo
Date: Wed Jan 27 2016 - 03:27:47 EST


Hi Shannon,

On 2016/1/23 11:19, Shannon Zhao wrote:
From: Shannon Zhao <shannon.zhao@xxxxxxxxxx>

When it's a Xen domain0 booting with ACPI, it will supply a /chosen and
a /hypervisor node in DT. So check if it needs to enable ACPI.

Signed-off-by: Shannon Zhao <shannon.zhao@xxxxxxxxxx>
---
CC: Hanjun Guo <hanjun.guo@xxxxxxxxxx>
---
arch/arm64/kernel/acpi.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kernel/acpi.c b/arch/arm64/kernel/acpi.c
index d1ce8e2..4e92be0 100644
--- a/arch/arm64/kernel/acpi.c
+++ b/arch/arm64/kernel/acpi.c
@@ -67,10 +67,13 @@ static int __init dt_scan_depth1_nodes(unsigned long node,
{
/*
* Return 1 as soon as we encounter a node at depth 1 that is
- * not the /chosen node.
+ * not the /chosen node, or /hypervisor node when running on Xen.

The comment is bit misleading, we need to specify two mode, running on
Xen or not, if not on xen, then /chosen node is enough.

*/
- if (depth == 1 && (strcmp(uname, "chosen") != 0))
- return 1;
+ if (depth == 1 && (strcmp(uname, "chosen") != 0)) {
+ if (!xen_initial_domain() || (strcmp(uname, "hypervisor") != 0))
+ return 1;
+ }
+
return 0;
}

@@ -184,7 +187,8 @@ void __init acpi_boot_table_init(void)
/*
* Enable ACPI instead of device tree unless
* - ACPI has been disabled explicitly (acpi=off), or
- * - the device tree is not empty (it has more than just a /chosen node)
+ * - the device tree is not empty (it has more than just a /chosen node,
+ * and a /hypervisor node when running on Xen)

and here too.

if that is addressed,

Acked-by: Hanjun Guo <hanjun.guo@xxxxxxxxxx>

Thanks
Hanjun