Commit 9bfc8da0 authored Sep 01, 2012 by Henrik Rydberg Committed by Jiri Kosina Sep 02, 2012

HID: Only dump input if someone is listening



Going through the motions of printing the debug message information
takes a long time; using the keyboard can lead to a 160 us irqsoff
latency. This patch skips hid_dump_input() when there are no open
handles, which brings latency down to 100 us.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

parent 67ddbb3e

drivers/hid/hid-core.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -996,6 +996,7 @@ static void hid_process_event(struct hid_device hid, struct hid_field field,
		struct hid_driver *hdrv = hid->driver;
		int ret;

		if (!list_empty(&hid->debug_list))
		hid_dump_input(hid, usage, value);

		if (hdrv && hdrv->event && hid_match_usage(hid, usage)) {