7 files changed, 103 insertions, 8 deletions

diff --git a/drivers/acpi/resources/rscalc.c b/drivers/acpi/resources/rscalc.c
index dcc51e92ac92..db0a835e3317 100644
--- a/drivers/acpi/resources/rscalc.c
+++ b/drivers/acpi/resources/rscalc.c
@@ -211,6 +211,13 @@ acpi_rs_get_aml_length(struct acpi_resource * resource, acpi_size * size_needed)
                  * variable-length fields
                  */
                 switch (resource->type) {
+                case ACPI_RESOURCE_TYPE_IRQ:
+
+                        if (resource->data.irq.descriptor_length == 2) {
+                                total_size--;
+                        }
+                        break;
+
                 case ACPI_RESOURCE_TYPE_VENDOR:
                         /*
                          * Vendor Defined Resource:
diff --git a/drivers/acpi/resources/rsdump.c b/drivers/acpi/resources/rsdump.c
index 46da116a4030..ed6447dcea78 100644
--- a/drivers/acpi/resources/rsdump.c
+++ b/drivers/acpi/resources/rsdump.c
@@ -87,8 +87,10 @@ acpi_rs_dump_descriptor(void *resource, struct acpi_rsdump_info *table);
  *
  ******************************************************************************/
 
-struct acpi_rsdump_info acpi_rs_dump_irq[6] = {
+struct acpi_rsdump_info acpi_rs_dump_irq[7] = {
         {ACPI_RSD_TITLE, ACPI_RSD_TABLE_SIZE(acpi_rs_dump_irq), "IRQ", NULL},
+        {ACPI_RSD_UINT8, ACPI_RSD_OFFSET(irq.descriptor_length),
+         "Descriptor Length", NULL},
         {ACPI_RSD_1BITFLAG, ACPI_RSD_OFFSET(irq.triggering), "Triggering",
          acpi_gbl_he_decode},
         {ACPI_RSD_1BITFLAG, ACPI_RSD_OFFSET(irq.polarity), "Polarity",
@@ -115,9 +117,11 @@ struct acpi_rsdump_info acpi_rs_dump_dma[6] = {
          NULL}
 };
 
-struct acpi_rsdump_info acpi_rs_dump_start_dpf[3] = {
+struct acpi_rsdump_info acpi_rs_dump_start_dpf[4] = {
         {ACPI_RSD_TITLE, ACPI_RSD_TABLE_SIZE(acpi_rs_dump_start_dpf),
          "Start-Dependent-Functions", NULL},
+        {ACPI_RSD_UINT8, ACPI_RSD_OFFSET(start_dpf.descriptor_length),
+         "Descriptor Length", NULL},
         {ACPI_RSD_2BITFLAG, ACPI_RSD_OFFSET(start_dpf.compatibility_priority),
          "Compatibility Priority", acpi_gbl_config_decode},
         {ACPI_RSD_2BITFLAG, ACPI_RSD_OFFSET(start_dpf.performance_robustness),
diff --git a/drivers/acpi/resources/rsio.c b/drivers/acpi/resources/rsio.c
index b297bc3e4419..50f3acdd9c8e 100644
--- a/drivers/acpi/resources/rsio.c
+++ b/drivers/acpi/resources/rsio.c
@@ -185,7 +185,7 @@ struct acpi_rsconvert_info acpi_rs_convert_end_tag[2] = {
  *
  ******************************************************************************/
 
-struct acpi_rsconvert_info acpi_rs_get_start_dpf[5] = {
+struct acpi_rsconvert_info acpi_rs_get_start_dpf[6] = {
         {ACPI_RSC_INITGET, ACPI_RESOURCE_TYPE_START_DEPENDENT,
          ACPI_RS_SIZE(struct acpi_resource_start_dependent),
          ACPI_RSC_TABLE_SIZE(acpi_rs_get_start_dpf)},
@@ -196,6 +196,12 @@ struct acpi_rsconvert_info acpi_rs_get_start_dpf[5] = {
          ACPI_ACCEPTABLE_CONFIGURATION,
          2},
 
+        /* Get the descriptor length (0 or 1 for Start Dpf descriptor) */
+
+        {ACPI_RSC_1BITFLAG, ACPI_RS_OFFSET(data.start_dpf.descriptor_length),
+         AML_OFFSET(start_dpf.descriptor_type),
+         0},
+
         /* All done if there is no flag byte present in the descriptor */
 
         {ACPI_RSC_EXIT_NE, ACPI_RSC_COMPARE_AML_LENGTH, 0, 1},
@@ -219,7 +225,9 @@ struct acpi_rsconvert_info acpi_rs_get_start_dpf[5] = {
  *
  ******************************************************************************/
 
-struct acpi_rsconvert_info acpi_rs_set_start_dpf[6] = {
+struct acpi_rsconvert_info acpi_rs_set_start_dpf[10] = {
+        /* Start with a default descriptor of length 1 */
+
         {ACPI_RSC_INITSET, ACPI_RESOURCE_NAME_START_DEPENDENT,
          sizeof(struct aml_resource_start_dependent),
          ACPI_RSC_TABLE_SIZE(acpi_rs_set_start_dpf)},
@@ -236,6 +244,33 @@ struct acpi_rsconvert_info acpi_rs_set_start_dpf[6] = {
          AML_OFFSET(start_dpf.flags),
          2},
         /*
+         * All done if the output descriptor length is required to be 1
+         * (i.e., optimization to 0 bytes cannot be attempted)
+         */
+        {ACPI_RSC_EXIT_EQ, ACPI_RSC_COMPARE_VALUE,
+         ACPI_RS_OFFSET(data.start_dpf.descriptor_length),
+         1},
+
+        /* Set length to 0 bytes (no flags byte) */
+
+        {ACPI_RSC_LENGTH, 0, 0,
+         sizeof(struct aml_resource_start_dependent_noprio)},
+
+        /*
+         * All done if the output descriptor length is required to be 0.
+         *
+         * TBD: Perhaps we should check for error if input flags are not
+         * compatible with a 0-byte descriptor.
+         */
+        {ACPI_RSC_EXIT_EQ, ACPI_RSC_COMPARE_VALUE,
+         ACPI_RS_OFFSET(data.start_dpf.descriptor_length),
+         0},
+
+        /* Reset length to 1 byte (descriptor with flags byte) */
+
+        {ACPI_RSC_LENGTH, 0, 0, sizeof(struct aml_resource_irq)},
+
+        /*
          * All done if flags byte is necessary -- if either priority value
          * is not ACPI_ACCEPTABLE_CONFIGURATION
          */
diff --git a/drivers/acpi/resources/rsirq.c b/drivers/acpi/resources/rsirq.c
index 5657f7b95039..382a77b8400d 100644
--- a/drivers/acpi/resources/rsirq.c
+++ b/drivers/acpi/resources/rsirq.c
@@ -52,7 +52,7 @@ ACPI_MODULE_NAME("rsirq")
  * acpi_rs_get_irq
  *
  ******************************************************************************/
-struct acpi_rsconvert_info acpi_rs_get_irq[7] = {
+struct acpi_rsconvert_info acpi_rs_get_irq[8] = {
         {ACPI_RSC_INITGET, ACPI_RESOURCE_TYPE_IRQ,
          ACPI_RS_SIZE(struct acpi_resource_irq),
          ACPI_RSC_TABLE_SIZE(acpi_rs_get_irq)},
@@ -69,6 +69,12 @@ struct acpi_rsconvert_info acpi_rs_get_irq[7] = {
          ACPI_EDGE_SENSITIVE,
          1},
 
+        /* Get the descriptor length (2 or 3 for IRQ descriptor) */
+
+        {ACPI_RSC_2BITFLAG, ACPI_RS_OFFSET(data.irq.descriptor_length),
+         AML_OFFSET(irq.descriptor_type),
+         0},
+
         /* All done if no flag byte present in descriptor */
 
         {ACPI_RSC_EXIT_NE, ACPI_RSC_COMPARE_AML_LENGTH, 0, 3},
@@ -94,7 +100,9 @@ struct acpi_rsconvert_info acpi_rs_get_irq[7] = {
  *
  ******************************************************************************/
 
-struct acpi_rsconvert_info acpi_rs_set_irq[9] = {
+struct acpi_rsconvert_info acpi_rs_set_irq[13] = {
+        /* Start with a default descriptor of length 3 */
+
         {ACPI_RSC_INITSET, ACPI_RESOURCE_NAME_IRQ,
          sizeof(struct aml_resource_irq),
          ACPI_RSC_TABLE_SIZE(acpi_rs_set_irq)},
@@ -105,7 +113,7 @@ struct acpi_rsconvert_info acpi_rs_set_irq[9] = {
          AML_OFFSET(irq.irq_mask),
          ACPI_RS_OFFSET(data.irq.interrupt_count)},
 
-        /* Set the flags byte by default */
+        /* Set the flags byte */
 
         {ACPI_RSC_1BITFLAG, ACPI_RS_OFFSET(data.irq.triggering),
          AML_OFFSET(irq.flags),
@@ -118,6 +126,33 @@ struct acpi_rsconvert_info acpi_rs_set_irq[9] = {
         {ACPI_RSC_1BITFLAG, ACPI_RS_OFFSET(data.irq.sharable),
          AML_OFFSET(irq.flags),
          4},
+
+        /*
+         * All done if the output descriptor length is required to be 3
+         * (i.e., optimization to 2 bytes cannot be attempted)
+         */
+        {ACPI_RSC_EXIT_EQ, ACPI_RSC_COMPARE_VALUE,
+         ACPI_RS_OFFSET(data.irq.descriptor_length),
+         3},
+
+        /* Set length to 2 bytes (no flags byte) */
+
+        {ACPI_RSC_LENGTH, 0, 0, sizeof(struct aml_resource_irq_noflags)},
+
+        /*
+         * All done if the output descriptor length is required to be 2.
+         *
+         * TBD: Perhaps we should check for error if input flags are not
+         * compatible with a 2-byte descriptor.
+         */
+        {ACPI_RSC_EXIT_EQ, ACPI_RSC_COMPARE_VALUE,
+         ACPI_RS_OFFSET(data.irq.descriptor_length),
+         2},
+
+        /* Reset length to 3 bytes (descriptor with flags byte) */
+
+        {ACPI_RSC_LENGTH, 0, 0, sizeof(struct aml_resource_irq)},
+
         /*
          * Check if the flags byte is necessary. Not needed if the flags are:
          * ACPI_EDGE_SENSITIVE, ACPI_ACTIVE_HIGH, ACPI_EXCLUSIVE
@@ -134,7 +169,7 @@ struct acpi_rsconvert_info acpi_rs_set_irq[9] = {
          ACPI_RS_OFFSET(data.irq.sharable),
          ACPI_EXCLUSIVE},
 
-        /* irq_no_flags() descriptor can be used */
+        /* We can optimize to a 2-byte irq_no_flags() descriptor */
 
         {ACPI_RSC_LENGTH, 0, 0, sizeof(struct aml_resource_irq_noflags)}
 };
diff --git a/drivers/acpi/resources/rsmisc.c b/drivers/acpi/resources/rsmisc.c
index c7081afa893a..3e69eff303fb 100644
--- a/drivers/acpi/resources/rsmisc.c
+++ b/drivers/acpi/resources/rsmisc.c
@@ -497,6 +497,17 @@ acpi_rs_convert_resource_to_aml(struct acpi_resource *resource,
                         }
                         break;
 
+                case ACPI_RSC_EXIT_EQ:
+                        /*
+                         * Control - Exit conversion if equal
+                         */
+                        if (*ACPI_ADD_PTR(u8, resource,
+                                          COMPARE_TARGET(info)) ==
+                            COMPARE_VALUE(info)) {
+                                goto exit;
+                        }
+                        break;
+
                 default:
 
                         ACPI_ERROR((AE_INFO, "Invalid conversion opcode"));
diff --git a/include/acpi/acresrc.h b/include/acpi/acresrc.h
index 9486ab266a5e..33e9f3813220 100644
--- a/include/acpi/acresrc.h
+++ b/include/acpi/acresrc.h
@@ -94,6 +94,7 @@ typedef const struct acpi_rsconvert_info {
 #define ACPI_RSC_BITMASK16              18
 #define ACPI_RSC_EXIT_NE                19
 #define ACPI_RSC_EXIT_LE                20
+#define ACPI_RSC_EXIT_EQ                21
 
 /* Resource Conversion sub-opcodes */
 
diff --git a/include/acpi/actypes.h b/include/acpi/actypes.h
index bb44700680a3..599657eac2d4 100644
--- a/include/acpi/actypes.h
+++ b/include/acpi/actypes.h
@@ -986,6 +986,7 @@ struct acpi_vendor_uuid {
  *  Structures used to describe device resources
  */
 struct acpi_resource_irq {
+        u8 descriptor_length;
         u8 triggering;
         u8 polarity;
         u8 sharable;
@@ -1002,6 +1003,7 @@ struct acpi_resource_dma {
 };
 
 struct acpi_resource_start_dependent {
+        u8 descriptor_length;
         u8 compatibility_priority;
         u8 performance_robustness;
 };