ACPICA: Windows compatibility fix: same buffer/string store

Commit Message

Lin Ming Aug. 26, 2009, 1:01 a.m. UTC

Hi, Len

This is the important fix for the WMI based HotKey issue reported by Dell.
Could you merge it to 2.6.31-rc8?

Thanks,
Lin Ming
---

Subject: [PATCH] ACPICA: Windows compatibility fix: same buffer/string store

Fixes a compatibility issue when the same buffer or string is
stored to itself. This has been seen in the field. Previously,
ACPICA would zero out the buffer/string. Now, the operation is
treated as a noop. ACPICA BZ 803.

http://bugzilla.acpica.org/show_bug.cgi?id=803

Signed-off-by: Lin Ming <[e-mail]>
Signed-off-by: Bob Moore <[e-mail]>
---
 drivers/acpi/acpica/exstorob.c |   12 ++++++++++++
 1 files changed, 12 insertions(+), 0 deletions(-)



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Comments

Len Brown Aug. 27, 2009, 2:29 p.m. UTC | #1

applied for 2.6.31

thanks,
Len Brown, Intel Open Source Technology Center

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Patch

diff --git a/drivers/acpi/acpica/exstorob.c b/drivers/acpi/acpica/exstorob.c
index 67340cc..257706e 100644
--- a/drivers/acpi/acpica/exstorob.c
+++ b/drivers/acpi/acpica/exstorob.c
@@ -70,6 +70,12 @@  acpi_ex_store_buffer_to_buffer(union acpi_operand_object *source_desc,
 
 	ACPI_FUNCTION_TRACE_PTR(ex_store_buffer_to_buffer, source_desc);
 
+	/* If Source and Target are the same, just return */
+
+	if (source_desc == target_desc) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
 	/* We know that source_desc is a buffer by now */
 
 	buffer = ACPI_CAST_PTR(u8, source_desc->buffer.pointer);
@@ -161,6 +167,12 @@  acpi_ex_store_string_to_string(union acpi_operand_object *source_desc,
 
 	ACPI_FUNCTION_TRACE_PTR(ex_store_string_to_string, source_desc);
 
+	/* If Source and Target are the same, just return */
+
+	if (source_desc == target_desc) {
+		return_ACPI_STATUS(AE_OK);
+	}
+
 	/* We know that source_desc is a string by now */
 
 	buffer = ACPI_CAST_PTR(u8, source_desc->string.pointer);