Re: [PATCH] HID: magicmouse: ignore 'ivalid report id' while switching modes

[Jaikumar Ganesh <jaikumarg@android.com>]

Hi Jiri,

On Tue, Aug 23, 2011 at 1:53 AM, Jiri Kosina <jkosina@suse.cz> wrote:
> On Thu, 18 Aug 2011, Jaikumar Ganesh wrote:
>
>> I also tracked down two Apple magic trackpads - both with the same
>> Bluetooth version.
>> One which needs this patch (as it returns an invalid report id) and
>> the other which doesn't need this patch.
>> Both use the same device id.
>
> Gotta love hardware vendors indeed.
>
> So how about the patch below?
>
>
>
> From: Jiri Kosina <jkosina@suse.cz>
> Subject: [PATCH] HID: magicmouse: ignore 'ivalid report id' while switching modes, v2
>
> This is basically a more generic respin of 23746a6 ("HID: magicmouse: ignore
> 'ivalid report id' while switching modes") which got reverted later by
> c3a492.
>
> It turns out that on some configurations, this is actually still the case
> and we are not able to detect in runtime.
>
> The device reponds with 'invalid report id' when feature report switching it
> into multitouch mode is sent to it.
>
> This has been silently ignored before 0825411ade ("HID: bt: Wait for ACK
> on Sent Reports"), but since this commit, it propagates -EIO from the _raw
> callback .
>
> So let the driver ignore -EIO as response to 0xd7,0x01 report, as that's
> how the device reacts in normal mode.
>
> Sad, but following reality.
>
> This fixes https://bugzilla.kernel.org/show_bug.cgi?id=35022
>
> Reported-by: Chase Douglas <chase.douglas@canonical.com>
> Reported-by: Jaikumar Ganesh <jaikumarg@android.com>
> Tested-by: Chase Douglas <chase.douglas@canonical.com>
> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
> ---
>  drivers/hid/hid-magicmouse.c |   10 +++++++++-
>  1 files changed, 9 insertions(+), 1 deletions(-)
>
> diff --git a/drivers/hid/hid-magicmouse.c b/drivers/hid/hid-magicmouse.c
> index b5bdab3..f0fbd7b 100644
> --- a/drivers/hid/hid-magicmouse.c
> +++ b/drivers/hid/hid-magicmouse.c
> @@ -537,9 +537,17 @@ static int magicmouse_probe(struct hid_device *hdev,
>        }
>        report->size = 6;
>
> +       /*
> +        * Some devices repond with 'invalid report id' when feature
> +        * report switching it into multitouch mode is sent to it.
> +        *
> +        * This results in -EIO from the _raw low-level transport callback,
> +        * but there seems to be no other way of switching the mode.
> +        * Thus the super-ugly hacky success check below.
> +        */
>        ret = hdev->hid_output_raw_report(hdev, feature, sizeof(feature),
>                        HID_FEATURE_REPORT);
> -       if (ret != sizeof(feature)) {
> +       if (ret != -EIO && ret != sizeof(feature)) {
>                hid_err(hdev, "unable to request touch data (%d)\n", ret);
>                goto err_stop_hw;
>        }
> --
> 1.7.3.1
>
>

Tested. Please push.

Thanks
Jaikumar
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