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Subject[PATCH 3/3] HID: usbhid: defer LED setting to a workqueue
Date
Defer LED setting action to a workqueue.
This is more likely to send all LED change events in a single URB.

Signed-off-by: Daniel Kurtz <djkurtz@chromium.org>
---
drivers/hid/hid-input.c | 42 ++++++++++++++++++++++++++++++++++++
drivers/hid/usbhid/hid-core.c | 47 +++++++++++++++++++++++++++++++---------
drivers/hid/usbhid/usbhid.h | 2 +
include/linux/hid.h | 2 +
4 files changed, 82 insertions(+), 11 deletions(-)

diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index 6e32526..9509684 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -867,6 +867,48 @@ int hidinput_find_field(struct hid_device *hid, unsigned int type, unsigned int
}
EXPORT_SYMBOL_GPL(hidinput_find_field);

+struct hid_field *hidinput_get_led_field(struct hid_device *hid)
+{
+ struct hid_report *report;
+ struct hid_field *field;
+ int i, j;
+
+ list_for_each_entry(report,
+ &hid->report_enum[HID_OUTPUT_REPORT].report_list,
+ list) {
+ for (i = 0; i < report->maxfield; i++) {
+ field = report->field[i];
+ for (j = 0; j < field->maxusage; j++)
+ if (field->usage[j].type == EV_LED)
+ return field;
+ }
+ }
+ return NULL;
+}
+EXPORT_SYMBOL_GPL(hidinput_get_led_field);
+
+unsigned int hidinput_count_leds(struct hid_device *hid)
+{
+ struct hid_report *report;
+ struct hid_field *field;
+ int i, j;
+ unsigned int count = 0;
+
+ list_for_each_entry(report,
+ &hid->report_enum[HID_OUTPUT_REPORT].report_list,
+ list) {
+ for (i = 0; i < report->maxfield; i++) {
+ field = report->field[i];
+ for (j = 0; j < field->maxusage; j++)
+ if (field->usage[j].type == EV_LED &&
+ field->value[j])
+ count += 1;
+ }
+ }
+ return count;
+}
+EXPORT_SYMBOL_GPL(hidinput_count_leds);
+
static int hidinput_open(struct input_dev *dev)
{
struct hid_device *hid = input_get_drvdata(dev);
diff --git a/drivers/hid/usbhid/hid-core.c b/drivers/hid/usbhid/hid-core.c
index 719f6b0..5bf91db 100644
--- a/drivers/hid/usbhid/hid-core.c
+++ b/drivers/hid/usbhid/hid-core.c
@@ -602,6 +602,30 @@ void usbhid_submit_report(struct hid_device *hid, struct hid_report *report, uns
}
EXPORT_SYMBOL_GPL(usbhid_submit_report);

+/* Workqueue routine to send requests to change LEDs */
+static void hid_led(struct work_struct *work)
+{
+ struct usbhid_device *usbhid =
+ container_of(work, struct usbhid_device, led_work);
+ struct hid_device *hid = usbhid->hid;
+ struct hid_field *field;
+ unsigned long flags;
+
+ field = hidinput_get_led_field(hid);
+ if (!field) {
+ hid_warn(hid, "LED event field not found\n");
+ return;
+ }
+
+ spin_lock_irqsave(&usbhid->lock, flags);
+ if (!test_bit(HID_DISCONNECTED, &usbhid->iofl)) {
+ usbhid->ledcount = hidinput_count_leds(hid);
+ hid_dbg(usbhid->hid, "New ledcount = %u\n", usbhid->ledcount);
+ __usbhid_submit_report(hid, field->report, USB_DIR_OUT);
+ }
+ spin_unlock_irqrestore(&usbhid->lock, flags);
+}
+
static int usb_hidinput_input_event(struct input_dev *dev, unsigned int type, unsigned int code, int value)
{
struct hid_device *hid = input_get_drvdata(dev);
@@ -621,17 +645,15 @@ static int usb_hidinput_input_event(struct input_dev *dev, unsigned int type, un
return -1;
}

+ spin_lock_irqsave(&usbhid->lock, flags);
hid_set_field(field, offset, value);
- if (value) {
- spin_lock_irqsave(&usbhid->lock, flags);
- usbhid->ledcount++;
- spin_unlock_irqrestore(&usbhid->lock, flags);
- } else {
- spin_lock_irqsave(&usbhid->lock, flags);
- usbhid->ledcount--;
- spin_unlock_irqrestore(&usbhid->lock, flags);
- }
- usbhid_submit_report(hid, field->report, USB_DIR_OUT);
+ spin_unlock_irqrestore(&usbhid->lock, flags);
+
+ /*
+ * Defer performing requested LED action.
+ * This is more likely gather all LED changes into a single URB.
+ */
+ schedule_work(&usbhid->led_work);

return 0;
}
@@ -1126,7 +1148,7 @@ static void usbhid_stop(struct hid_device *hid)
return;

clear_bit(HID_STARTED, &usbhid->iofl);
- spin_lock_irq(&usbhid->lock); /* Sync with error handler */
+ spin_lock_irq(&usbhid->lock); /* Sync with error and led handlers */
set_bit(HID_DISCONNECTED, &usbhid->iofl);
spin_unlock_irq(&usbhid->lock);
usb_kill_urb(usbhid->urbin);
@@ -1260,6 +1282,8 @@ static int usbhid_probe(struct usb_interface *intf, const struct usb_device_id *
setup_timer(&usbhid->io_retry, hid_retry_timeout, (unsigned long) hid);
spin_lock_init(&usbhid->lock);

+ INIT_WORK(&usbhid->led_work, hid_led);
+
ret = hid_add_device(hid);
if (ret) {
if (ret != -ENODEV)
@@ -1292,6 +1316,7 @@ static void hid_cancel_delayed_stuff(struct usbhid_device *usbhid)
{
del_timer_sync(&usbhid->io_retry);
cancel_work_sync(&usbhid->reset_work);
+ cancel_work_sync(&usbhid->led_work);
}

static void hid_cease_io(struct usbhid_device *usbhid)
diff --git a/drivers/hid/usbhid/usbhid.h b/drivers/hid/usbhid/usbhid.h
index 2d8957c..cb8f703 100644
--- a/drivers/hid/usbhid/usbhid.h
+++ b/drivers/hid/usbhid/usbhid.h
@@ -96,6 +96,8 @@ struct usbhid_device {
struct work_struct reset_work; /* Task context for resets */
wait_queue_head_t wait; /* For sleeping */
int ledcount; /* counting the number of active leds */
+
+ struct work_struct led_work; /* Task context for setting LEDs */
};

#define hid_to_usb_dev(hid_dev) \
diff --git a/include/linux/hid.h b/include/linux/hid.h
index deed5f9..0df7d62 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -711,6 +711,8 @@ extern void hidinput_disconnect(struct hid_device *);
int hid_set_field(struct hid_field *, unsigned, __s32);
int hid_input_report(struct hid_device *, int type, u8 *, int, int);
int hidinput_find_field(struct hid_device *hid, unsigned int type, unsigned int code, struct hid_field **field);
+struct hid_field *hidinput_get_led_field(struct hid_device *hid);
+unsigned int hidinput_count_leds(struct hid_device *hid);
void hid_output_report(struct hid_report *report, __u8 *data);
struct hid_device *hid_allocate_device(void);
struct hid_report *hid_register_report(struct hid_device *device, unsigned type, unsigned id);
--
1.7.3.1


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