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Diffstat (limited to 'drivers/acpi/acpica/exregion.c')
-rw-r--r--drivers/acpi/acpica/exregion.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/drivers/acpi/acpica/exregion.c b/drivers/acpi/acpica/exregion.c
index 1db2c0bfde0b..0a01e19c3190 100644
--- a/drivers/acpi/acpica/exregion.c
+++ b/drivers/acpi/acpica/exregion.c
@@ -142,9 +142,9 @@ acpi_ex_system_memory_space_handler(u32 function,
}
/*
- * Attempt to map from the requested address to the end of the region.
- * However, we will never map more than one page, nor will we cross
- * a page boundary.
+ * October 2009: Attempt to map from the requested address to the
+ * end of the region. However, we will never map more than one
+ * page, nor will we cross a page boundary.
*/
map_length = (acpi_size)
((mem_info->address + mem_info->length) - address);
@@ -154,7 +154,11 @@ acpi_ex_system_memory_space_handler(u32 function,
* a page boundary, just map up to the page boundary, do not cross.
* On some systems, crossing a page boundary while mapping regions
* can cause warnings if the pages have different attributes
- * due to resource management
+ * due to resource management.
+ *
+ * This has the added benefit of constraining a single mapping to
+ * one page, which is similar to the original code that used a 4k
+ * maximum window.
*/
page_boundary_map_length =
ACPI_ROUND_UP(address, ACPI_DEFAULT_PAGE_SIZE) - address;