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.
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@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);
--
2.17.0.441.gb46fe60e1d-goog
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