perf Documentation: Clarify sysfs event names characters

Specify that perf event names in sysfs must not contain mixed lower and
upper case characters and that they may contain numbers, ".", "_",
or "-" as well.

Fixes: 785623ee855e893d ("perf Document: Sysfs event names must be lower or upper case")
Reviewed-by: Ian Rogers <irogers@google.com>
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Link: https://lore.kernel.org/r/20240513192439.18473-1-rdunlap@infradead.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
index e7efeab2ee83ce79eaaa0d9a71f32ce93bcb93b1..0fe1b94872025861e04a0c35b1211d501f34dd58 100644 (file)
--- a/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
+++ b/Documentation/ABI/testing/sysfs-bus-event_source-devices-events
@@ -37,11 +37,13 @@ Description:        Per-pmu performance monitoring events specific to the running syste
                performance monitoring event supported by the <pmu>. The name
                of the file is the name of the event.
 
-               As performance monitoring event names are case
-               insensitive in the perf tool, the perf tool only looks
-               for lower or upper case event names in sysfs to avoid
+               As performance monitoring event names are case insensitive
+               in the perf tool, the perf tool only looks for all lower
+               case or all upper case event names in sysfs to avoid
                scanning the directory. It is therefore required the
-               name of the event here is either lower or upper case.
+               name of the event here is either completely lower or upper
+               case, with no mixed-case characters. Numbers, '.', '_', and
+               '-' are also allowed.
 
                File contents: