# HG changeset patch
# Parent 1126b3079bef37e1bb5a97b90c14a51d4e1c91c3
docs/command line: Clarify the behavior with invalid input.

Signed-off-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>

diff -r 1126b3079bef docs/misc/xen-command-line.markdown
--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -11,7 +11,8 @@ Hypervisor.
 ## Types of parameter
 
 Most parameters take the form `option=value`.  Different options on
-the command line should be space delimited.
+the command line should be space delimited.  All options are case
+sensitive, as are all values unless explicitly noted.
 
 ### Boolean (`<boolean>`)
 
@@ -68,6 +69,39 @@ Some options take a comma separated list
 Some parameters act as combinations of the above, most commonly a mix
 of Boolean and String.  These are noted in the relevant sections.
 
+## Unexpected input
+
+This information describes the behaviour with unexpected or malformed
+input, for reference purposes.  It is not expected to be used in any
+situation, nor relied upon.
+
+### Boolean
+
+* `<values>` other than those listed will invert the option, so take
+  its non-default value.
+
+* A `no-` prefix can be stacked with an explicit `=<value>`.
+ * A `no-<option>=0` will cancel, so the option takes its default
+   value.
+ * A `no-<option>=1` will invert the option, so take its non-default
+   value.
+
+### Integer
+
+Input which cannot be converted to a valid number will result in the
+parameter being set to 0.  Strings which start as a valid integer but
+contain invalid characters as a suffix will have the suffix ignored.
+
+### Size
+
+Unrecognised suffixes will be ignored, and the default suffix will be
+used.
+
+### Strings, Lists and Combinations
+
+Depending on implementation, strings may be truncated or ignored all
+together as if the option were not specified in the first place.
+
 ## Parameter details
 
 ### acpi