memory-id: Work-around incorrect "Number of slots"

hadess · bluca · commit d48bf01636d3 · 2022-03-07T15:33:26.000Z
In some BIOSes, the "Number of slots or sockets available for Memory Devices in this array" is incorrectly set to the number of memory array that's populated. Work-around this problem by outputting the number of sockets after having parsed them so that consumers of this data can carry on expecting an accurate number in this property. This fixes the number of memory slots advertised for the HP Z600. See https://gitlab.gnome.org/GNOME/gnome-control-center/-/issues/1686
diff --git a/src/udev/dmi_memory_id/dmi_memory_id.c b/src/udev/dmi_memory_id/dmi_memory_id.c
@@ -417,9 +417,9 @@ static void dmi_memory_device_size_detail(
                 dmi_print_memory_size("MEMORY_DEVICE", attr_suffix, slot_num, code, MEMORY_SIZE_UNIT_BYTES);
 }
 
-static void dmi_decode(const struct dmi_header *h) {
+static void dmi_decode(const struct dmi_header *h,
+                       unsigned *next_slot_num) {
         const uint8_t *data = h->data;
-        static unsigned next_slot_num = 0;
         unsigned slot_num;
 
         /*
@@ -441,15 +441,14 @@ static void dmi_decode(const struct dmi_header *h) {
                         dmi_print_memory_size("MEMORY_ARRAY", "MAX_CAPACITY", -1, DWORD(data + 0x07), MEMORY_SIZE_UNIT_KB);
                 else if (h->length >= 0x17)
                         dmi_print_memory_size("MEMORY_ARRAY", "MAX_CAPACITY", -1, QWORD(data + 0x0F), MEMORY_SIZE_UNIT_BYTES);
-                printf("MEMORY_ARRAY_NUM_DEVICES=%u\n", WORD(data + 0x0D));
 
                 break;
 
         case 17: /* 7.18 Memory Device */
-                slot_num = next_slot_num;
-                next_slot_num++;
+                slot_num = *next_slot_num;
+                *next_slot_num = slot_num + 1;
 
-                log_debug("Memory Device");
+                log_debug("Memory Device: %u", slot_num);
                 if (h->length < 0x15)
                         break;
 
@@ -525,6 +524,7 @@ static void dmi_decode(const struct dmi_header *h) {
 
 static void dmi_table_decode(const uint8_t *buf, size_t len, uint16_t num) {
         const uint8_t *data = buf;
+        unsigned next_slot_num = 0;
 
         /* 4 is the length of an SMBIOS structure header */
         for (uint16_t i = 0; (i < num || num == 0) && data + 4 <= buf + len; i++) {
@@ -559,10 +559,12 @@ static void dmi_table_decode(const uint8_t *buf, size_t len, uint16_t num) {
                         break;
 
                 if (display)
-                        dmi_decode(&h);
+                        dmi_decode(&h, &next_slot_num);
 
                 data = next;
         }
+        if (next_slot_num > 0)
+                printf("MEMORY_ARRAY_NUM_DEVICES=%u\n", next_slot_num);
 }
 
 static int dmi_table(int64_t base, uint32_t len, uint16_t num, const char *devmem, bool no_file_offset) {
diff --git a/test/dmidecode-dumps/HP-Z600.bin.txt b/test/dmidecode-dumps/HP-Z600.bin.txt
@@ -1,11 +1,9 @@
 MEMORY_ARRAY_LOCATION=System Board Or Motherboard
 MEMORY_ARRAY_EC_TYPE=Multi-bit ECC
 MEMORY_ARRAY_MAX_CAPACITY=12884901888
-MEMORY_ARRAY_NUM_DEVICES=3
 MEMORY_ARRAY_LOCATION=System Board Or Motherboard
 MEMORY_ARRAY_EC_TYPE=Multi-bit ECC
 MEMORY_ARRAY_MAX_CAPACITY=12884901888
-MEMORY_ARRAY_NUM_DEVICES=3
 MEMORY_DEVICE_0_TOTAL_WIDTH=72
 MEMORY_DEVICE_0_DATA_WIDTH=64
 MEMORY_DEVICE_0_SIZE=8589934592
@@ -92,3 +90,4 @@ MEMORY_DEVICE_6_MANUFACTURER=Not Specified
 MEMORY_DEVICE_6_SERIAL_NUMBER=Not Specified
 MEMORY_DEVICE_6_ASSET_TAG=Not Specified
 MEMORY_DEVICE_6_PART_NUMBER=Not Specified
+MEMORY_ARRAY_NUM_DEVICES=7
diff --git a/test/dmidecode-dumps/Lenovo-ThinkPad-X280.bin.txt b/test/dmidecode-dumps/Lenovo-ThinkPad-X280.bin.txt
@@ -1,6 +1,5 @@
 MEMORY_ARRAY_LOCATION=System Board Or Motherboard
 MEMORY_ARRAY_MAX_CAPACITY=34359738368
-MEMORY_ARRAY_NUM_DEVICES=2
 MEMORY_DEVICE_0_TOTAL_WIDTH=64
 MEMORY_DEVICE_0_DATA_WIDTH=64
 MEMORY_DEVICE_0_SIZE=4294967296
@@ -31,3 +30,4 @@ MEMORY_DEVICE_1_ASSET_TAG=None
 MEMORY_DEVICE_1_RANK=1
 MEMORY_DEVICE_1_CONFIGURED_SPEED_MTS=2400
 MEMORY_DEVICE_1_CONFIGURED_VOLTAGE=1
+MEMORY_ARRAY_NUM_DEVICES=2
diff --git a/test/dmidecode-dumps/Lenovo-Thinkcentre-m720s.bin.txt b/test/dmidecode-dumps/Lenovo-Thinkcentre-m720s.bin.txt
@@ -1,6 +1,5 @@
 MEMORY_ARRAY_LOCATION=System Board Or Motherboard
 MEMORY_ARRAY_MAX_CAPACITY=68719476736
-MEMORY_ARRAY_NUM_DEVICES=4
 MEMORY_DEVICE_0_TOTAL_WIDTH=64
 MEMORY_DEVICE_0_DATA_WIDTH=64
 MEMORY_DEVICE_0_SIZE=8589934592
@@ -65,3 +64,4 @@ MEMORY_DEVICE_3_CONFIGURED_SPEED_MTS=2400
 MEMORY_DEVICE_3_MINIMUM_VOLTAGE=1
 MEMORY_DEVICE_3_MAXIMUM_VOLTAGE=1
 MEMORY_DEVICE_3_CONFIGURED_VOLTAGE=1
+MEMORY_ARRAY_NUM_DEVICES=4
