Messages in this thread Patch in this message | | | From | "Henrik Rydberg" <> | Subject | [PATCH 17/20] HID: Only dump input if someone is listening | Date | Sun, 26 Aug 2012 14:57:35 +0200 |
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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> --- drivers/hid/hid-core.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c index 60ea284..5b74e78 100644 --- a/drivers/hid/hid-core.c +++ b/drivers/hid/hid-core.c @@ -996,7 +996,8 @@ static void hid_process_event(struct hid_device *hid, struct hid_field *field, struct hid_driver *hdrv = hid->driver; int ret; - hid_dump_input(hid, usage, value); + if (!list_empty(&hid->debug_list)) + hid_dump_input(hid, usage, value); if (hdrv && hdrv->event && hid_match_usage(hid, usage)) { ret = hdrv->event(hid, field, usage, value); -- 1.7.12
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