diff mbox

[2/2] goldfish_events: no extra EV_SYN; register goldfish

Message ID 20180531233707.80702-2-rkir@google.com (mailing list archive)
State New, archived
Headers show

Commit Message

Roman Kiryanov May 31, 2018, 11:37 p.m. UTC
From: Lingfeng Yang <lfy@google.com>

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.

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.

Signed-off-by: "Lingfeng Yang" <lfy@google.com>
Signed-off-by: Roman Kiryanov <rkir@google.com>
---
 drivers/input/keyboard/goldfish_events.c | 28 +++++++++++++++++++++++-
 1 file changed, 27 insertions(+), 1 deletion(-)

Comments

Dmitry Torokhov June 1, 2018, 12:01 a.m. UTC | #1
Hi Roman,

On Thu, May 31, 2018 at 04:37:07PM -0700, rkir@google.com wrote:
> From: Lingfeng Yang <lfy@google.com>
> 
> 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@google.com>
> Signed-off-by: Roman Kiryanov <rkir@google.com>
> ---
>  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.
diff mbox

Patch

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);