linux-kernel - Re: [PATCH v3 2/3] HID: quirks: Fix keyboard + touchpad on Lenovo Miix 630 for DT

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Message-ID: <CAO-hwJKeACBPW52ej6mVeG4aVDYvGF8zEMtegonVwFjT-ZoLOQ@mail.gmail.com>
Date:   Thu, 18 Apr 2019 11:34:47 +0200
From:   Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:     Jeffrey Hugo <jeffrey.l.hugo@...il.com>,
        Hans de Goede <hdegoede@...hat.com>
Cc:     Rob Herring <robh+dt@...nel.org>, mark.rutland@....com,
        Jiri Kosina <jikos@...nel.org>,
        Lee Jones <lee.jones@...aro.org>, bjorn.andersson@...aro.org,
        Dmitry Torokhov <dmitry.torokhov@...il.com>, agross@...nel.org,
        david.brown@...aro.org,
        "open list:HID CORE LAYER" <linux-input@...r.kernel.org>,
        devicetree@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        lkml <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3 2/3] HID: quirks: Fix keyboard + touchpad on Lenovo
 Miix 630 for DT

On Mon, Apr 15, 2019 at 6:11 PM Jeffrey Hugo <jeffrey.l.hugo@...il.com> wrote:
>
> Following up on commit 2bafa1e96254 ("HID: quirks: Fix keyboard + touchpad
> on Lenovo Miix 630"), the devicetree (DT) identifier for the combo keyboard
> + touchpad device is "elan,combo400-i2c", which differs from the ACPI ID,
> thus if we want the quirk to work properly when booting via DT instead of
> ACPI, we need to key off the DT id as well.
>
> Signed-off-by: Jeffrey Hugo <jeffrey.l.hugo@...il.com>
> ---
>  drivers/hid/hid-quirks.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/hid-quirks.c b/drivers/hid/hid-quirks.c
> index 77ffba48cc73..00c08f8318b8 100644
> --- a/drivers/hid/hid-quirks.c
> +++ b/drivers/hid/hid-quirks.c
> @@ -997,7 +997,8 @@ bool hid_ignore(struct hid_device *hdev)
>                         return true;
>                 /* Same with product id 0x0400 */
>                 if (hdev->product == 0x0400 &&
> -                   strncmp(hdev->name, "QTEC0001", 8) != 0)
> +                   (strncmp(hdev->name, "QTEC0001", 8) != 0 ||
> +                    strncmp(hdev->name, "elan,combo400-i2c", 17) != 0))

I think we are taking the problem the wrong way here.

When I first introduced 6ccfe64, I thought 0x0400 would be reserved
for the elan_i2c touchpads only. But it turns out we are deliberately
disabling valid HID touchpads hoping that they would be picked up by
elan_i2c when elan_i2c has its own whitelist of devices.

How about we turn this into list with the matching ones from elan_i2c:
if ((hdev->product == 0x0400 || hdev->product == 0x0401) &&
   (strncmp(hdev->name, "ELAN0000", 8) == 0 ||
    strncmp(hdev->name, "ELAN0100", 8) == 0 ||
    ...
    strncmp(hdev->name, "ELAN1000", 8) == 0))
      return true;

So next time we need to force binding a HID touchpad to elan_i2c, we
can just blacklist here and whitelist it in elan_i2c.

Cheers,
Benjamin

>                         return true;
>                 break;
>         }
> --
> 2.17.1
>