From: Lingfeng Yang <lfy@xxxxxxxxxx>
If we send SYN_REPORT on every single multi-touch event, it breaks the
multi-touch.
The multi-touch becomes jerky and you have to click 2-3 times to do things
while randomly activating notification bars when not clicking.
If we suppress these SYN_REPORTS, multi-touch will work fine and the events
will have a protocol that looks nice.
We need to register Goldfish Events as a multi-touch 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, causing touches of more than one
finger to fail.
Signed-off-by: Lingfeng Yang <lfy@xxxxxxxxxx>
Signed-off-by: Jin Qian <jinqian@xxxxxxxxxxx>
Signed-off-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
---
drivers/input/keyboard/goldfish_events.c | 30 +++++++++++++++++++++++++++++-
1 file changed, 29 insertions(+), 1 deletion(-)
diff --git a/drivers/input/keyboard/goldfish_events.c b/drivers/input/keyboard/goldfish_events.c
index c7e308a..c0d77b7 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 +55,23 @@ 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;
}
@@ -154,6 +173,15 @@ 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.
+ * 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.
+ * See drivers/input/input.c:input_handle_abs_event.
+ */
+ 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);
--
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