diff --git a/qemu-options.hx b/qemu-options.hx
index c77f868..d86815d 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1074,12 +1074,17 @@
 ETEXI
 
 DEF("acpitable", HAS_ARG, QEMU_OPTION_acpitable,
-    "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,data=file1[:file2]...]\n"
+    "-acpitable [sig=str][,rev=n][,oem_id=str][,oem_table_id=str][,oem_rev=n][,asl_compiler_id=str][,asl_compiler_rev=n][,{data|file}=file1[:file2]...]\n"
     "                ACPI table description\n", QEMU_ARCH_I386)
 STEXI
 @item -acpitable [sig=@var{str}][,rev=@var{n}][,oem_id=@var{str}][,oem_table_id=@var{str}][,oem_rev=@var{n}] [,asl_compiler_id=@var{str}][,asl_compiler_rev=@var{n}][,data=@var{file1}[:@var{file2}]...]
 @findex -acpitable
 Add ACPI table with specified header fields and context from specified files.
+For file=, take whole ACPI table from the specified files, including all
+ACPI headers (possible overridden by other options).
+For data=, only data
+portion of the table is used, all header information is specified in the
+command line.
 ETEXI
 
 DEF("smbios", HAS_ARG, QEMU_OPTION_smbios,