According to the ARM IORT specifications DEN 0049 issue E, the "Number of IDs" field in the ID mapping format reports the number of IDs in the mapping range minus one. In iort_node_get_rmr_info(), we erroneously skip ID mappings whose "Number of IDs" equal to 0, resulting in valid mapping nodes with a single ID to map being skipped, which is wrong. Fix iort_node_get_rmr_info() by removing the bogus id_count check. Fixes: 491cf4a6735a ("ACPI/IORT: Add support to retrieve IORT RMR reserved regions") Signed-off-by: Guanghui Feng <guanghuifeng@xxxxxxxxxxxxxxxxx> --- drivers/acpi/arm64/iort.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/acpi/arm64/iort.c b/drivers/acpi/arm64/iort.c index 3631230..56d8873 100644 --- a/drivers/acpi/arm64/iort.c +++ b/drivers/acpi/arm64/iort.c @@ -1007,9 +1007,6 @@ static void iort_node_get_rmr_info(struct acpi_iort_node *node, for (i = 0; i < node->mapping_count; i++, map++) { struct acpi_iort_node *parent; - if (!map->id_count) - continue; - parent = ACPI_ADD_PTR(struct acpi_iort_node, iort_table, map->output_reference); if (parent != iommu) -- 1.8.3.1