linux-kernel - Re: [PATCH] i2c-hid: Fix "incomplete report" noise

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Date:   Mon, 9 Jul 2018 08:14:34 -0400
From:   Jason Andryuk <jandryuk@...il.com>
To:     open list <linux-kernel@...r.kernel.org>,
        Jiri Kosina <jikos@...nel.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>
Cc:     john-s-84@....net, Jason Andryuk <jandryuk@...il.com>,
        stable@...r.kernel.org, linux-input@...r.kernel.org
Subject: Re: [PATCH] i2c-hid: Fix "incomplete report" noise

Ping?

The logging here is very excessive.  If not this change, then some
other change is needed to cut down on the sheer quantity of messages.

Thanks,
Jason


On Fri, Jun 22, 2018 at 12:25 PM, Jason Andryuk <jandryuk@...il.com> wrote:
> Commit ac75a041048b ("HID: i2c-hid: fix size check and type usage")
> started writing messages when the ret_size is <= 2 from i2c_master_recv.
> However, my device i2c-DLL07D1 returns 2 for a short period of time
> (~0.5s) after I stop moving the pointing stick or touchpad.  It varies,
> but you get ~50 messages each time which spams the log hard.
> [  95.925055] i2c_hid i2c-DLL07D1:01: i2c_hid_get_input: incomplete report (83/2)
>
> This has also been observed with a i2c-ALP0017.
> [ 1781.266353] i2c_hid i2c-ALP0017:00: i2c_hid_get_input: incomplete report (30/2)
>
> Only print the message when ret_size is totally invalid and less than 2
> to cut down on the log spam.
>
> Reported-by: John Smith <john-s-84@....net>
> Cc: stable@...r.kernel.org
> Signed-off-by: Jason Andryuk <jandryuk@...il.com>
> ---
> John Smith originally reported this, but his post did not include a git
> formatted patch nor a Signed-off-by.
> https://www.spinics.net/lists/linux-input/msg56171.html
> https://patchwork.kernel.org/patch/10374383/
>
> When ret_size is 2, hid_input_report is passed 0 and returns early.  ret_size
> == 2 seems to be a header size saying there is no content.  Should
> i2c_hid_get_input just return early in that case?
>
> Also, should this condition be noted to stop an interrupt from firing to
> avoid the ~50 bogus messages?
>
>  drivers/hid/i2c-hid/i2c-hid.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid.c b/drivers/hid/i2c-hid/i2c-hid.c
> index c1652bb7bd15..eae0cb3ddec6 100644
> --- a/drivers/hid/i2c-hid/i2c-hid.c
> +++ b/drivers/hid/i2c-hid/i2c-hid.c
> @@ -484,7 +484,7 @@ static void i2c_hid_get_input(struct i2c_hid *ihid)
>                 return;
>         }
>
> -       if ((ret_size > size) || (ret_size <= 2)) {
> +       if ((ret_size > size) || (ret_size < 2)) {
>                 dev_err(&ihid->client->dev, "%s: incomplete report (%d/%d)\n",
>                         __func__, size, ret_size);
>                 return;
> --
> 2.17.1
>