Re: [PATCH v3 16/20] HID: Only dump input if someone is listening

From: Jiri Kosina
Date: Sun Sep 02 2012 - 03:28:31 EST


On Sat, 1 Sep 2012, Henrik Rydberg wrote:

> 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@xxxxxxxxxxx>
> ---
> 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);

Henrik,

I have applied this one right away, so you can drop it from your series.
The remaining ones I am still about to review (currently travelling).

There is no inter-dependency between the Input and HID ones, and so we can
handle them with Dmitry as two independent Input and HID series, right?

Thanks a lot,

--
Jiri Kosina
SUSE Labs
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