On Fri, 14 Dec 2018, Kai-Heng Feng wrote:
> While using Elan touchpads, the message floods:
> [ 136.138487] i2c_hid i2c-DELL08D6:00: i2c_hid_get_input: incomplete report
> (14/65535)
>
> Though the message flood is annoying, the device it self works without
> any issue. I suspect that the device in question takes too much time to
> pull the IRQ back to high after I2C host has done reading its data.
>
> Since the host receives all useful data, let's ignore the input report
> when there's no data.
Interesting, never seen such a bug before.
> Signed-off-by: Kai-Heng Feng <kai.heng.f...@canonical.com>
> ---
> drivers/hid/i2c-hid/i2c-hid-core.c | 9 +++++++++
> 1 file changed, 9 insertions(+)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c
> b/drivers/hid/i2c-hid/i2c-hid-core.c
> index 8555ce7e737b..1776afa6d69c 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
> @@ -50,6 +50,7 @@
> #define I2C_HID_QUIRK_NO_IRQ_AFTER_RESET BIT(1)
> #define I2C_HID_QUIRK_NO_RUNTIME_PM BIT(2)
> #define I2C_HID_QUIRK_DELAY_AFTER_SLEEP BIT(3)
> +#define I2C_HID_QUIRK_BOGUS_IRQ BIT(4)
>
> /* flags */
> #define I2C_HID_STARTED 0
> @@ -179,6 +180,8 @@ static const struct i2c_hid_quirks {
> I2C_HID_QUIRK_DELAY_AFTER_SLEEP },
> { USB_VENDOR_ID_LG, I2C_DEVICE_ID_LG_8001,
> I2C_HID_QUIRK_NO_RUNTIME_PM },
> + { USB_VENDOR_ID_ELAN, HID_ANY_ID,
> + I2C_HID_QUIRK_BOGUS_IRQ },
> { 0, 0 }
> };
>
> @@ -503,6 +506,12 @@ static void i2c_hid_get_input(struct i2c_hid *ihid)
> return;
> }
>
> + if (ihid->quirks & I2C_HID_QUIRK_BOGUS_IRQ && ret_size == 0xffff) {
> + dev_dbg(&ihid->client->dev,
> + "%s: IRQ triggered but there's no data\n", __func__);
> + return;
> + }
Would it perhaps make sense to make this some sort of printk_once(), so
that it's immediately apparent from dmesg that the system/device is
suffering from this particular problem? Might potentially be helpful piece
of information.
Thanks,
--
Jiri Kosina
SUSE Labs
