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Subject: Re: [PATCH RESEND v2] virtio-input: add multi-touch support
To:     Dmitry Torokhov <dmitry.torokhov@gmail.com>
CC:     <virtualization@lists.linux-foundation.org>,
        <linux-kernel@vger.kernel.org>, <linux-input@vger.kernel.org>,
        "Michael S. Tsirkin" <mst@redhat.com>,
        Jason Wang <jasowang@redhat.com>,
        Gerd Hoffmann <kraxel@redhat.com>,
        Henrik Rydberg <rydberg@bitmath.org>,
        Mathias Crombez <mathias.crombez@faurecia.com>
References: <20201208210150.20001-1-vasyl.vavrychuk@opensynergy.com>
 <X8/4kRLsr8755i01@google.com>
From:   Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>
Message-ID: <c1f764da-9923-9073-0001-757587f53853@opensynergy.com>
Date:   Sat, 19 Dec 2020 01:20:30 +0200
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Hi, Dmitry,

Thanks for you suggestion. I have sent v3 version of the patch where I 
have applied it.

Kind regards,
Vasyl

On 09.12.20 00:05, Dmitry Torokhov wrote:
> CAUTION: This email originated from outside of the organization.
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> 
> 
> Hi Vasyl,
> 
> On Tue, Dec 08, 2020 at 11:01:50PM +0200, Vasyl Vavrychuk wrote:
>> From: Mathias Crombez <mathias.crombez@faurecia.com>
>>
>> Without multi-touch slots allocated, ABS_MT_SLOT events will be lost by
>> input_handle_abs_event.
>>
>> Signed-off-by: Mathias Crombez <mathias.crombez@faurecia.com>
>> Signed-off-by: Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>
>> Tested-by: Vasyl Vavrychuk <vasyl.vavrychuk@opensynergy.com>
>> ---
>> v2: fix patch corrupted by corporate email server
>>
>>   drivers/virtio/Kconfig        | 11 +++++++++++
>>   drivers/virtio/virtio_input.c |  8 ++++++++
>>   2 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/virtio/Kconfig b/drivers/virtio/Kconfig
>> index 7b41130d3f35..2cfd5b01d96d 100644
>> --- a/drivers/virtio/Kconfig
>> +++ b/drivers/virtio/Kconfig
>> @@ -111,6 +111,17 @@ config VIRTIO_INPUT
>>
>>         If unsure, say M.
>>
>> +config VIRTIO_INPUT_MULTITOUCH_SLOTS
>> +     depends on VIRTIO_INPUT
>> +     int "Number of multitouch slots"
>> +     range 0 64
>> +     default 10
>> +     help
>> +      Define the number of multitouch slots used. Default to 10.
>> +      This parameter is unused if there is no multitouch capability.
> 
> I believe the number of slots should be communicated to the guest by
> the host, similarly to how the rest of input device capabilities is
> transferred, instead of having static compile-time option.
> 
>> +
>> +      0 will disable the feature.
>> +
>>   config VIRTIO_MMIO
>>        tristate "Platform bus driver for memory mapped virtio devices"
>>        depends on HAS_IOMEM && HAS_DMA
>> diff --git a/drivers/virtio/virtio_input.c b/drivers/virtio/virtio_input.c
>> index f1f6208edcf5..13f3d90e6c30 100644
>> --- a/drivers/virtio/virtio_input.c
>> +++ b/drivers/virtio/virtio_input.c
>> @@ -7,6 +7,7 @@
>>
>>   #include <uapi/linux/virtio_ids.h>
>>   #include <uapi/linux/virtio_input.h>
>> +#include <linux/input/mt.h>
>>
>>   struct virtio_input {
>>        struct virtio_device       *vdev;
>> @@ -205,6 +206,7 @@ static int virtinput_probe(struct virtio_device *vdev)
>>        unsigned long flags;
>>        size_t size;
>>        int abs, err;
>> +     bool is_mt = false;
>>
>>        if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1))
>>                return -ENODEV;
>> @@ -287,9 +289,15 @@ static int virtinput_probe(struct virtio_device *vdev)
>>                for (abs = 0; abs < ABS_CNT; abs++) {
>>                        if (!test_bit(abs, vi->idev->absbit))
>>                                continue;
>> +                     if (input_is_mt_value(abs))
>> +                             is_mt = true;
>>                        virtinput_cfg_abs(vi, abs);
>>                }
>>        }
>> +     if (is_mt)
>> +             input_mt_init_slots(vi->idev,
>> +                                 CONFIG_VIRTIO_INPUT_MULTITOUCH_SLOTS,
>> +                                 INPUT_MT_DIRECT);
> 
> Here errors need to be handled.
> 
>>
>>        virtio_device_ready(vdev);
>>        vi->ready = true;
>> --
>> 2.23.0
>>
> 
> Thanks.
> 
> --
> Dmitry
>