diff mbox

[v7,6/8] acpi: fix "Memory device control fields" register

Message ID fd59052cf04c9f62c62aefd5369162ef7ac8a356.1430097856.git.zhugh.fnst@cn.fujitsu.com
State New
Headers show

Commit Message

Zhu Guihua April 27, 2015, 8:47 a.m. UTC 
0 bit in Memory device control fields must be cleared before writing to
register. But now this field isn't cleared when other fields are written.

To solve this bug, This patch fixes UpdateRule to WriteAsZeros in "Memory
device control fields" register.

Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Signed-off-by: Zhu Guihua <zhugh.fnst@cn.fujitsu.com>
---
 docs/specs/acpi_mem_hotplug.txt | 5 ++++-
 hw/i386/acpi-build.c            | 2 +-
 2 files changed, 5 insertions(+), 2 deletions(-)
diff mbox

Patch

diff --git a/docs/specs/acpi_mem_hotplug.txt b/docs/specs/acpi_mem_hotplug.txt
index dcc4808..68daa14 100644
--- a/docs/specs/acpi_mem_hotplug.txt
+++ b/docs/specs/acpi_mem_hotplug.txt
@@ -31,7 +31,10 @@  Memory hot-plug interface (IO port 0xa00-0xa17, 1-4 byte access):
       [0xc-0x13] reserved, writes into it are ignored
       [0x14] Memory device control fields
           bits:
-              0: reserved, OSPM must clear it before writing to register
+              0: reserved, OSPM must clear it before writing to register.
+                 Due to BUG in versions prior 2.4 that field isn't cleared
+                 when other fields are written. Keep it reserved and don't
+                 try to reuse it.
               1: if set to 1 clears device insert event, set by OSPM
                  after it has emitted device check event for the
                  selected memory device
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index dc1b8e8..eb66fef 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -924,7 +924,7 @@  build_ssdt(GArray *table_data, GArray *linker,
         aml_append(scope, field);
 
         field = aml_field(stringify(MEMORY_HOTPLUG_IO_REGION), aml_byte_acc,
-                          aml_preserve);
+                          aml_write_as_zeros);
         aml_append(field, aml_reserved_field(160 /* bits, Offset(20) */));
         aml_append(field, /* 1 if enabled, read only */
             aml_named_field(stringify(MEMORY_SLOT_ENABLED), 1));