From: Roderick Colenbrander <thunderbird2k@gmail.com>
To: Henry Castro <hcvcastro@gmail.com>
Cc: Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
linux-input <linux-input@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] drivers/hid: avoid invalid denominator
Date: Mon, 26 Apr 2021 09:36:56 -0700 [thread overview]
Message-ID: <CAEc3jaB+wNp1Fa-_P=XcYxRNL+L4z_M_wsW6iODyyHz90Xq-vw@mail.gmail.com> (raw)
In-Reply-To: <CAF44FUyskn-g+MUYONMXYZ8dUiGFd0GF1wkkPQwd34ikbet_Fg@mail.gmail.com>
Hm, I'm a little confused then. The Shanwan gamepad is a Dualshock 3
clone (nickname 'sixaxis'), so should not go through the DualShock 4
paths. Can you double check what the vendor / device id for this
device are? Are you seeing specific errors or warnings from the driver
in the kernel logs?
I have been considering how to better handle some of these clones
devices, while also not polluting the code too much. If this device is
indeed a clone DualShock 4. I am more leaning towards finding out
sooner during device creation. Perhaps should not even create a motion
sensor device if the data will be none anyway... Hm, not sure what I
prefer yet.
Thanks,
Roderick
On Sun, Apr 25, 2021 at 9:39 AM Henry Castro <hcvcastro@gmail.com> wrote:
>
> Hi,
>
> I was trying to play some old games from Retroarch, and I plugged
> my "SHANWAN PS3 GamePad", but it begin to vibrate and I could
> not play the games, So I started to investigate and read the source
> code, and get the code to bypass the check, and suddenly I got
> a panic crash. So I found the issue, and I added the patch, finally
> got working, and I played my favorite old games.
>
> So it happens in PS3 clone device I think, but I have to tweak the code
> probably is safe under the condition you mention in PS4 DualShock,
> but it is good as a prevention, if someone is testing and debugging
> the driver.
>
> Regards
> Henry
>
> El sáb, 24 abr 2021 a las 17:11, Roderick Colenbrander (<thunderbird2k@gmail.com>) escribió:
>>
>> Hi Henry,
>>
>> Thanks for your patch. In what case has this been an issue? Or was it
>> more theoretical.
>>
>> During normal operation this condition should never be triggered for a
>> DualShock 4 when calibration succeeds. If it doesn't succeed the
>> device is not registered. We had an issue recently with the DS4 dongle
>> where the calibration data was 0, which was due to a race condition
>> with Steam, but that was resolved recently.
>>
>> Thanks,
>> Roderick
>>
>> On Sun, Apr 11, 2021 at 10:19 AM Henry Castro <hcvcastro@gmail.com> wrote:
>> >
>> > Avoid a potential panic in case wrong denominator
>> > is given.
>> >
>> > Signed-off-by: Henry Castro <hcvcastro@gmail.com>
>> > ---
>> > drivers/hid/hid-sony.c | 13 +++++++++----
>> > 1 file changed, 9 insertions(+), 4 deletions(-)
>> >
>> > diff --git a/drivers/hid/hid-sony.c b/drivers/hid/hid-sony.c
>> > index 8319b0ce385a..67b45d82cc3b 100644
>> > --- a/drivers/hid/hid-sony.c
>> > +++ b/drivers/hid/hid-sony.c
>> > @@ -1134,11 +1134,16 @@ static void dualshock4_parse_report(struct sony_sc *sc, u8 *rd, int size)
>> > * Note: we swap numerator 'x' and 'numer' in mult_frac for
>> > * precision reasons so we don't need 64-bit.
>> > */
>> > - int calib_data = mult_frac(calib->sens_numer,
>> > - raw_data - calib->bias,
>> > - calib->sens_denom);
>> > + if (calib->sens_denom != 0) {
>> > + int calib_data = mult_frac(calib->sens_numer,
>> > + raw_data - calib->bias,
>> > + calib->sens_denom);
>> > +
>> > + input_report_abs(sc->sensor_dev, calib->abs_code, calib_data);
>> > + } else {
>> > + hid_warn(sc->hdev, "DualShock 4 parse report, avoid invalid denominator");
>> > + }
>> >
>> > - input_report_abs(sc->sensor_dev, calib->abs_code, calib_data);
>> > offset += 2;
>> > }
>> > input_sync(sc->sensor_dev);
>> > --
>> > 2.20.1
>> >
prev parent reply other threads:[~2021-04-26 16:37 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-11 15:06 [PATCH] drivers/hid: avoid invalid denominator Henry Castro
2021-04-24 21:11 ` Roderick Colenbrander
[not found] ` <CAF44FUyskn-g+MUYONMXYZ8dUiGFd0GF1wkkPQwd34ikbet_Fg@mail.gmail.com>
2021-04-26 16:36 ` Roderick Colenbrander [this message]
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