linux-kernel - Re: [PATCH v3] HID: i2c-hid: Skip ELAN power-on command after reset

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Date:   Fri, 7 May 2021 15:38:36 +0200
From:   Benjamin Tissoires <benjamin.tissoires@...hat.com>
To:     Johnny Chuang <johnny.chuang.emc@...il.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Peter Hutterer <peter.hutterer@...-t.net>,
        lkml <linux-kernel@...r.kernel.org>,
        "open list:HID CORE LAYER" <linux-input@...r.kernel.org>,
        Harry Cutts <hcutts@...omium.org>,
        Johnny Chuang <johnny.chuang@....com.tw>,
        James Chen <james.chen@....com.tw>,
        Jennifer Tsai <jennifer.tsai@....com.tw>,
        Paul Liang <paul.liang@....com.tw>,
        Jeff Chuang <jeff.chuang@....com.tw>,
        Douglas Anderson <dianders@...omium.org>,
        Jingle <jingle.wu@....com.tw>
Subject: Re: [PATCH v3] HID: i2c-hid: Skip ELAN power-on command after reset

Hi Johnny,

Apologies fo the delay.

When I first saw your patch I wondered why we need a  special case for Elan.
But then, we need a special case for SIS, as mentioned by
43b7029f475e. Given that this patch was in for a year and a half, and
not many people seemed to complain about it, I decided to apply your
patch.


On Tue, Apr 13, 2021 at 3:21 AM Johnny Chuang
<johnny.chuang.emc@...il.com> wrote:
>
> Fixes: 43b7029f475e ("HID: i2c-hid: Send power-on command after reset").

As requested per Doug, I have moved that Fixes tag at the end, though
I forgot to remove the extra '.' at the end :-(

>
> For ELAN touchscreen, we found our boot code of IC was not flexible enough
> to receive and handle this command.
> Once the FW main code of our controller is crashed for some reason,
> the controller could not be enumerated successfully to be recognized
> by the system host. therefore, it lost touch functionality.
>
> Add quirk for skip send power-on command after reset.
> It will impact to ELAN touchscreen and touchpad on HID over I2C projects.
>
> Signed-off-by: Johnny Chuang <johnny.chuang.emc@...il.com>
> ---
> Changes in V3:
>     - intent the comment at qurik entry
>     - add Fixes:flag for previous commit id
>
> Changes in v2:
>     - move comment to quirk entry
> ---
>  drivers/hid/i2c-hid/i2c-hid-core.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
> index 9993133..32e3287 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
> @@ -45,6 +45,7 @@
>  #define I2C_HID_QUIRK_BOGUS_IRQ                        BIT(4)
>  #define I2C_HID_QUIRK_RESET_ON_RESUME          BIT(5)
>  #define I2C_HID_QUIRK_BAD_INPUT_SIZE           BIT(6)
> +#define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET    BIT(7)
>
>
>  /* flags */
> @@ -178,6 +179,12 @@ static const struct i2c_hid_quirks {
>                  I2C_HID_QUIRK_RESET_ON_RESUME },
>         { USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
>                 I2C_HID_QUIRK_BAD_INPUT_SIZE },
> +       /*
> +        * Sending the wakeup after reset actually break ELAN touchscreen controller
> +        * Add I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET to skip wakeup after reset

I removed that extra second line.

Also added Cc: stable, and pushed to for-5.13/upstream-fixes

Cheers,
Benjamin

> +        */
> +       { USB_VENDOR_ID_ELAN, HID_ANY_ID,
> +                I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET },
>         { 0, 0 }
>  };
>
> @@ -461,7 +468,8 @@ static int i2c_hid_hwreset(struct i2c_client *client)
>         }
>
>         /* At least some SIS devices need this after reset */
> -       ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
> +       if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
> +               ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
>
>  out_unlock:
>         mutex_unlock(&ihid->reset_lock);
> --
> 2.7.4
>