#define GSMI_CMD_LOG_S0IX_RESUME 0x0b
#define GSMI_CMD_CLEAR_CONFIG 0x20
#define GSMI_CMD_HANDSHAKE_TYPE 0xC1
+#define GSMI_CMD_RESERVED 0xff
/* Magic entry type for kernel events */
#define GSMI_LOG_ENTRY_TYPE_KERNEL 0xDEAD
static __init int gsmi_system_valid(void)
{
u32 hash;
+ u16 cmd, result;
if (!dmi_check_system(gsmi_dmi_table))
return -ENODEV;
return -ENODEV;
}
+ /* Test the smihandler with a bogus command. If it leaves the
+ * calling argument in %ax untouched, there is no handler for
+ * GSMI commands.
+ */
+ cmd = GSMI_CALLBACK | GSMI_CMD_RESERVED << 8;
+ asm volatile (
+ "outb %%al, %%dx\n\t"
+ : "=a" (result)
+ : "0" (cmd),
+ "d" (acpi_gbl_FADT.smi_command)
+ : "memory", "cc"
+ );
+ if (cmd == result) {
+ pr_info("gsmi: no gsmi handler in firmware\n");
+ return -ENODEV;
+ }
+
/* Found */
return 0;
}