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Subject: Re: [PATCH v2 0/3] new driver for Valve Steam Controller
To:     Rodrigo Rivas Costa <rodrigorivascosta@gmail.com>,
        Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        <linux-kernel@vger.kernel.org>, <linux-input@vger.kernel.org>
References: <20180220193306.28748-1-rodrigorivascosta@gmail.com>
From:   "Pierre-Loup A. Griffais" <pgriffais@valvesoftware.com>
Message-ID: <673a2510-7d82-1b24-1085-9f5aa2bb9998@valvesoftware.com>
Date:   Tue, 20 Feb 2018 14:29:48 -0800
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Hi Rodrigo,

Thanks for working on that! I have a few questions and remarks.

For the reverse-engineering part, there's a lot of existing reference in=20
existing (user-space) drivers for the controllers like sc-controller,=20
but feel free to reach out if you have any questions. It's overall=20
pretty simple and there's nothing secret about how it functions; there=20
are some quirks, however. Nothing secret about it, but also no=20
documentation, so might as well be... Have you tried deflecting the=20
analog stick while touching the left trackpad? You'll most likely need=20
special handling there. How are you planning to expose=20
enabling/disabling auxiliary data like gyro over wireless?

Will this driver being loaded affect functionality of existing=20
applications that talk to it through HID directly, like Steam or=20
sc-controller? Will they be able to keep getting the same HID data they=20
do today? If so, the extent of the work needed to support it in Steam=20
might just be to ignore the controller device it's exposing, since Steam=20
will expose that itself through its own means.

Thanks,
  - Pierre-Loup

On 02/20/2018 11:33 AM, Rodrigo Rivas Costa wrote:
> This patchset implements a driver for Valve Steam Controller, based on a
> reverse analysis by myself.
>=20
> Notable changes from patchset v1:
>   * Remove references to USB. Now the interesting interfaces are selected=
 by
>     looking for the ones with feature reports.
>   * Feature reports buffers are allocated with hid_alloc_report_buf().
>   * Feature report length is checked, to avoid overflows in case of
>     corrupt/malicius USB devices.
>   * Resolution added to the ABS axes.
>   * A lot of minor cleanups.
>=20
> Rodrigo Rivas Costa (3):
>    HID: add driver for Valve Steam Controller
>    HID: steam: add serial number information.
>    HID: steam: add battery device.
>=20
>   drivers/hid/Kconfig      |   8 +
>   drivers/hid/Makefile     |   1 +
>   drivers/hid/hid-ids.h    |   4 +
>   drivers/hid/hid-quirks.c |   4 +
>   drivers/hid/hid-steam.c  | 703 ++++++++++++++++++++++++++++++++++++++++=
+++++++
>   5 files changed, 720 insertions(+)
>   create mode 100644 drivers/hid/hid-steam.c
>=20