Index: stand/i386/libi386/biosacpi.c
===================================================================
--- stand/i386/libi386/biosacpi.c
+++ stand/i386/libi386/biosacpi.c
@@ -38,6 +38,7 @@
 #define ACPI_SYSTEM_XFACE
 #include "actypes.h"
 #include "actbl.h"
+#include "actbl3.h"
 
 /*
  * Detect ACPI and export information about the ACPI BIOS into the
@@ -49,6 +50,94 @@
 
 #define RSDP_CHECKSUM_LENGTH 20
 
+static ACPI_TABLE_SPCR *
+find_spcr(ACPI_TABLE_RSDP *rsdp)
+{
+	unsigned count, i;
+	ACPI_TABLE_XSDT *xsdt;
+	ACPI_TABLE_RSDT *rsdt;
+	void *ptr;
+
+	if (rsdp->Revision >= 2 && rsdp->XsdtPhysicalAddress != 0) {
+		xsdt = (ACPI_TABLE_XSDT *)PTOV(rsdp->XsdtPhysicalAddress);
+
+		count = xsdt->Header.Length - sizeof(ACPI_TABLE_HEADER);
+		count /= sizeof(UINT64);
+		for (i = 0; i < count; i++) {
+			ptr = PTOV(xsdt->TableOffsetEntry[i]);
+			if (memcmp(ptr, ACPI_SIG_SPCR,
+			    sizeof(ACPI_SIG_SPCR) - 1) == 0) {
+				return (ptr);
+			}
+		}
+	}
+	if (rsdp->RsdtPhysicalAddress != 0) {
+
+		rsdt = (ACPI_TABLE_RSDT *)PTOV(rsdp->RsdtPhysicalAddress);
+
+		count = rsdt->Header.Length - sizeof(ACPI_TABLE_HEADER);
+		count /= sizeof(UINT32);
+		for (i = 0; i < count; i++) {
+			ptr = PTOV(rsdt->TableOffsetEntry[i]);
+			if (memcmp(ptr, ACPI_SIG_SPCR,
+			    sizeof(ACPI_SIG_SPCR) - 1) == 0) {
+				return (ptr);
+			}
+		}
+	}
+	return (NULL);
+}
+
+/*
+ * Find and parse SPCR table to set up serial console.
+ */
+static void
+biosacpi_setup_spcr(ACPI_TABLE_SPCR *spcr)
+{
+	unsigned baudrate;
+	char value[21];
+
+	if (spcr == NULL)
+		return;
+
+	switch (spcr->BaudRate) {
+	case 0:
+		baudrate = 0;
+		break;
+	case 3:
+		baudrate = 9600;
+		break;
+	case 4:
+		baudrate = 19200;
+		break;
+	case 6:
+		baudrate = 57600;
+		break;
+	case 7:
+		baudrate = 115200;
+		break;
+	default:
+		return;
+	}
+
+	switch (spcr->SerialPort.SpaceId) {
+	case ACPI_ADR_SPACE_SYSTEM_IO:
+		setenv("console", "comconsole", 1);
+		snprintf(value, sizeof(value), "%ju",
+		    (uintmax_t)spcr->SerialPort.Address);
+		setenv("comconsole_port", value, 1);
+		break;
+	default:
+		/* XXX not implemented. */
+		return;
+	}
+
+	if (baudrate > 0) {
+		snprintf(value, sizeof(value), "%u", baudrate);
+		setenv("comconsole_speed", value, 1);
+	}
+}
+
 void
 biosacpi_detect(void)
 {
@@ -95,6 +184,7 @@
 	setenv("hint.acpi.0.xsdt_length", buf, 1);
 	setenv("acpi.xsdt_length", buf, 1);
     }
+    biosacpi_setup_spcr(find_spcr(rsdp));
 }
 
 /*
Index: stand/i386/loader/main.c
===================================================================
--- stand/i386/loader/main.c
+++ stand/i386/loader/main.c
@@ -128,6 +128,12 @@
     setheap(heap_bottom, heap_top);
 
     /*
+     * detect ACPI for future reference. This may set console to comconsole
+     * if we do have ACPI SPCR table.
+     */
+    biosacpi_detect();
+
+    /*
      * XXX Chicken-and-egg problem; we want to have console output early, but some
      * console attributes may depend on reading from eg. the boot device, which we
      * can't do yet.
@@ -232,9 +238,6 @@
 	initial_bootinfo->bi_basemem = bios_basemem / 1024;
 	initial_bootinfo->bi_extmem = bios_extmem / 1024;
     }
-
-    /* detect ACPI for future reference */
-    biosacpi_detect();
 
     /* detect SMBIOS for future reference */
     smbios_detect(NULL);