Hi Roman,
On Thu, May 31, 2018 at 04:37:07PM -0700, rkir@xxxxxxxxxx wrote:
> From: Lingfeng Yang <lfy@xxxxxxxxxx>
>
> If we send SYN_REPORT on every single
> multitouch event, it breaks the multitouch.
>
> The multitouch becomes janky and
> having to click 2-3 times to
> do stuff (plus randomly activating notification
> bars when not clicking)
>
> If we suppress these SYN_REPORTS,
> multitouch will work fine, plus the events
> will have a protocol that looks nice.
I believe I mentioned this before: please fix goldfish backend. If it
decided to send input events it should follow the input protocol.
>
> In addition, we need to register Goldfish Events
> as a multitouch device by issuing
> input_mt_init_slots, otherwise
> input_handle_abs_event in drivers/input/input.c
> will silently drop all ABS_MT_SLOT events,
> making it so that touches with more than 1 finger
> do not work properly.
Can we extend the protocol to supply the expected number of contacts?
>
> Signed-off-by: "Lingfeng Yang" <lfy@xxxxxxxxxx>
> Signed-off-by: Roman Kiryanov <rkir@xxxxxxxxxx>
> ---
> drivers/input/keyboard/goldfish_events.c | 28 +++++++++++++++++++++++-
> 1 file changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/input/keyboard/goldfish_events.c b/drivers/input/keyboard/goldfish_events.c
> index e8dae6195b30..055accfeb0dd 100644
> --- a/drivers/input/keyboard/goldfish_events.c
> +++ b/drivers/input/keyboard/goldfish_events.c
> @@ -17,6 +17,7 @@
> #include <linux/interrupt.h>
> #include <linux/types.h>
> #include <linux/input.h>
> +#include <linux/input/mt.h>
> #include <linux/kernel.h>
> #include <linux/platform_device.h>
> #include <linux/slab.h>
> @@ -24,6 +25,8 @@
> #include <linux/io.h>
> #include <linux/acpi.h>
>
> +#define GOLDFISH_MAX_FINGERS 5
> +
> enum {
> REG_READ = 0x00,
> REG_SET_PAGE = 0x00,
> @@ -52,7 +55,21 @@ static irqreturn_t events_interrupt(int irq, void *dev_id)
> value = __raw_readl(edev->addr + REG_READ);
>
> input_event(edev->input, type, code, value);
> - input_sync(edev->input);
> + // Send an extra (EV_SYN, SYN_REPORT, 0x0) event
> + // if a key was pressed. Some keyboard device
> + // drivers may only send the EV_KEY event and
> + // not EV_SYN.
> + // Note that sending an extra SYN_REPORT is not
> + // necessary nor correct protocol with other
> + // devices such as touchscreens, which will send
> + // their own SYN_REPORT's when sufficient event
> + // information has been collected (e.g., for
> + // touchscreens, when pressure and X/Y coordinates
> + // have been received). Hence, we will only send
> + // this extra SYN_REPORT if type == EV_KEY.
> + if (type == EV_KEY)
> + input_sync(edev->input);
> +
> return IRQ_HANDLED;
> }
>
> @@ -155,6 +172,15 @@ static int events_probe(struct platform_device *pdev)
>
> input_dev->name = edev->name;
> input_dev->id.bustype = BUS_HOST;
> + // Set the Goldfish Device to be multi-touch.
> + // In the Ranchu kernel, there is multi-touch-specific
> + // code for handling ABS_MT_SLOT events.
> + // See drivers/input/input.c:input_handle_abs_event.
> + // If we do not issue input_mt_init_slots,
> + // the kernel will filter out needed ABS_MT_SLOT
> + // events when we touch the screen in more than one place,
> + // preventing multi-touch with more than one finger from working.
> + input_mt_init_slots(input_dev, GOLDFISH_MAX_FINGERS, 0);
>
> events_import_bits(edev, input_dev->evbit, EV_SYN, EV_MAX);
> events_import_bits(edev, input_dev->keybit, EV_KEY, KEY_MAX);
> --
> 2.17.0.921.gf22659ad46-goog
>
Thanks.
--
Dmitry
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