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Date:   Fri, 14 Dec 2018 14:34:09 +0100
From:   Aleix Roca Nonell <kernelrocks@gmail.com>
To:     Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc:     Jiri Kosina <jikos@kernel.org>,
        "open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
        lkml <linux-kernel@vger.kernel.org>, mbrugger@suse.com
Subject: Re: [PATCH] HID: asus: Add support for the ASUS T101HA keyboard dock
Message-ID: <20181214133409.GB4189@rocks>
References: <20181201190153.GB4995@arks.localdomain>
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 <CAO-hwJJRuBbHKCmW4vcmjdDkNEF0==wuLC5ymSkw8mOHnkdwwQ@mail.gmail.com>
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Hi Benjamin! :D

On Fri, Dec 14, 2018 at 09:25:20AM +0100, Benjamin Tissoires wrote:
> Hi Aleix,
> 
> On Fri, Dec 14, 2018 at 9:07 AM Aleix Roca Nonell <kernelrocks@gmail.com> wrote:
> >
> > Kind remminder ping :)
> 
> Hehe, I have seen the patch floating by and realized I would need more
> than 2 minutes to answer it so it fell a little bit behind in my TODO
> list.
> 
> Let's try to work on this now.
> 
> >
> > I'm also adding my fellow Matthias in CC
> >
> > On Sat, Dec 01, 2018 at 08:01:53PM +0100, Aleix Roca Nonell wrote:
> > > The ASUS T101HA keyboard dock generates HID events using the ASUS vendor
> > > specific UsagePage 0xff31. In consequence, some multimedia keys such as
> > > brightness up and down are not working with hid-generic.
> > >
> > > This commit adds the T101HA dock into the supported device list of the
> > > hid-asus driver. It also prevents the dock's integrated touchpad to be
> > > bound with hid-asus given that it is already working fine with
> > > hid-multitouch.
> > >
> > > Signed-off-by: Aleix Roca Nonell <kernelrocks@gmail.com>
> > > ---
> > >
> > > This is my very first kernel patch done in my free time (be aware of the
> > > newbie!!) so please, let me know if I can improve anything and I will
> > > happily do it :)
> > >
> > >  drivers/hid/hid-asus.c | 12 ++++++++++++
> > >  drivers/hid/hid-ids.h  |  1 +
> > >  2 files changed, 13 insertions(+)
> > >
> > > diff --git a/drivers/hid/hid-asus.c b/drivers/hid/hid-asus.c
> > > index ab8bd40a77ed..d8b55dca97c6 100644
> > > --- a/drivers/hid/hid-asus.c
> > > +++ b/drivers/hid/hid-asus.c
> > > @@ -42,6 +42,7 @@ MODULE_AUTHOR("Frederik Wenigwieser <frederik.wenigwieser@gmail.com>");
> > >  MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
> > >
> > >  #define T100_TPAD_INTF 2
> > > +#define T101HA_TPAD_INTF 2
> > >
> > >  #define T100CHI_MOUSE_REPORT_ID 0x06
> > >  #define FEATURE_REPORT_ID 0x0d
> > > @@ -70,6 +71,7 @@ MODULE_DESCRIPTION("Asus HID Keyboard and TouchPad");
> > >  #define QUIRK_T100_KEYBOARD          BIT(6)
> > >  #define QUIRK_T100CHI                        BIT(7)
> > >  #define QUIRK_G752_KEYBOARD          BIT(8)
> > > +#define QUIRK_T101HA_DOCK            BIT(9)
> > >
> > >  #define I2C_KEYBOARD_QUIRKS                  (QUIRK_FIX_NOTEBOOK_REPORT | \
> > >                                                QUIRK_NO_INIT_REPORTS | \
> > > @@ -649,6 +651,14 @@ static int asus_probe(struct hid_device *hdev, const struct hid_device_id *id)
> > >       int ret;
> > >       struct asus_drvdata *drvdata;
> > >
> > > +     if (id->driver_data & QUIRK_T101HA_DOCK) {
> > > +             struct usb_interface *intf = to_usb_interface(hdev->dev.parent);
> 
> I know the hid-asus driver already does this for the other devices,
> but it would be nice not to. USB is part of the low level transport
> and HID drivers should have no reasons to assume the USB driver is
> used and that it will stay forever.
> 
> What I ask when we have such a case is to check on the report
> descriptor to see if there is anything we could use in it (usually the
> application) to skip this HID interface.
> 
> Besides that, there is not much more to say.

Great I will do that!

> For having a look at the report descriptor, you can either use printk
> in the kernel, or use hid-recorder as root in
> https://gitlab.freedesktop.org/libevdev/hid-tools.

Regarding the descriptor, shouldn't be ok to check
/sys/kernel/debug/hid/<dev>/rdesc ?

Thank you!

> 
> Cheers,
> Benjamin
> 
> > > +
> > > +             /* use hid-multitouch for T101HA touchpad */
> > > +             if (intf->altsetting->desc.bInterfaceNumber == T101HA_TPAD_INTF)
> > > +                     return -ENODEV;
> > > +     }
> > > +
> > >       drvdata = devm_kzalloc(&hdev->dev, sizeof(*drvdata), GFP_KERNEL);
> > >       if (drvdata == NULL) {
> > >               hid_err(hdev, "Can't alloc Asus descriptor\n");
> > > @@ -830,6 +840,8 @@ static const struct hid_device_id asus_devices[] = {
> > >       { HID_USB_DEVICE(USB_VENDOR_ID_ASUSTEK,
> > >               USB_DEVICE_ID_ASUSTEK_T100TAF_KEYBOARD),
> > >         QUIRK_T100_KEYBOARD | QUIRK_NO_CONSUMER_USAGES },
> > > +     { HID_USB_DEVICE(USB_VENDOR_ID_ASUSTEK,
> > > +             USB_DEVICE_ID_ASUSTEK_T101HA_KEYBOARD), QUIRK_T101HA_DOCK },
> > >       { HID_USB_DEVICE(USB_VENDOR_ID_CHICONY, USB_DEVICE_ID_ASUS_AK1D) },
> > >       { HID_USB_DEVICE(USB_VENDOR_ID_TURBOX, USB_DEVICE_ID_ASUS_MD_5110) },
> > >       { HID_USB_DEVICE(USB_VENDOR_ID_JESS, USB_DEVICE_ID_ASUS_MD_5112) },
> > > diff --git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
> > > index 4206428c0ba2..f1eee2778b70 100644
> > > --- a/drivers/hid/hid-ids.h
> > > +++ b/drivers/hid/hid-ids.h
> > > @@ -184,6 +184,7 @@
> > >  #define USB_DEVICE_ID_ASUSTEK_T100TA_KEYBOARD        0x17e0
> > >  #define USB_DEVICE_ID_ASUSTEK_T100TAF_KEYBOARD       0x1807
> > >  #define USB_DEVICE_ID_ASUSTEK_T100CHI_KEYBOARD       0x8502
> > > +#define USB_DEVICE_ID_ASUSTEK_T101HA_KEYBOARD        0x183d
> > >  #define USB_DEVICE_ID_ASUSTEK_T304_KEYBOARD  0x184a
> > >  #define USB_DEVICE_ID_ASUSTEK_I2C_KEYBOARD   0x8585
> > >  #define USB_DEVICE_ID_ASUSTEK_I2C_TOUCHPAD   0x0101
> > > --
> > > 2.19.2
> > >