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HID: usbhid: do not sleep when opening device 

usbhid tries to give the device 50 milliseconds to drain its queues when
opening the device, but does it naively by simply sleeping in open handler,
which slows down device probing (and thus may affect overall boot time).

However we do not need to sleep as we can instead mark a point of time in
the future when we should start processing the events.

Reported-by: Nicolas Boichat <drinkcat@chromium.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Dmitry Torokhov 2020-06-09 21:38:24 -07:00 committed by Jiri Kosina
parent a789d5f8a9
commit d313279228
2 changed files with 31 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
drivers/hid/usbhid/hid-core.c
View File

@ -26,6 +26,7 @@
#include <linux/wait.h>
#include <linux/workqueue.h>
#include <linux/string.h>
#include <linux/timekeeping.h>
#include <linux/usb.h>
@ -95,6 +96,18 @@ static int hid_start_in(struct hid_device *hid)
set_bit(HID_NO_BANDWIDTH, &usbhid->iofl);
} else {
clear_bit(HID_NO_BANDWIDTH, &usbhid->iofl);
if (test_bit(HID_RESUME_RUNNING, &usbhid->iofl)) {
/*
* In case events are generated while nobody was
* listening, some are released when the device
* is re-opened. Wait 50 msec for the queue to
* empty before allowing events to go through
* hid.
*/
usbhid->input_start_time =
ktime_add_ms(ktime_get_coarse(), 50);
}
}
}
spin_unlock_irqrestore(&usbhid->lock, flags);
@ -280,20 +293,23 @@ static void hid_irq_in(struct urb *urb)
if (!test_bit(HID_OPENED, &usbhid->iofl))
break;
usbhid_mark_busy(usbhid);
if (!test_bit(HID_RESUME_RUNNING, &usbhid->iofl)) {
hid_input_report(urb->context, HID_INPUT_REPORT,
urb->transfer_buffer,
urb->actual_length, 1);
/*
* autosuspend refused while keys are pressed
* because most keyboards don't wake up when
* a key is released
*/
if (hid_check_keys_pressed(hid))
set_bit(HID_KEYS_PRESSED, &usbhid->iofl);
else
clear_bit(HID_KEYS_PRESSED, &usbhid->iofl);
if (test_bit(HID_RESUME_RUNNING, &usbhid->iofl)) {
if (ktime_before(ktime_get_coarse(),
usbhid->input_start_time))
break;
clear_bit(HID_RESUME_RUNNING, &usbhid->iofl);
}
hid_input_report(urb->context, HID_INPUT_REPORT,
urb->transfer_buffer, urb->actual_length, 1);
/*
* autosuspend refused while keys are pressed
* because most keyboards don't wake up when
* a key is released
*/
if (hid_check_keys_pressed(hid))
set_bit(HID_KEYS_PRESSED, &usbhid->iofl);
else
clear_bit(HID_KEYS_PRESSED, &usbhid->iofl);
break;
case -EPIPE: /* stall */
usbhid_mark_busy(usbhid);
@ -720,17 +736,6 @@ static int usbhid_open(struct hid_device *hid)
usb_autopm_put_interface(usbhid->intf);
/*
* In case events are generated while nobody was listening,
* some are released when the device is re-opened.
* Wait 50 msec for the queue to empty before allowing events
* to go through hid.
*/
if (res == 0)
msleep(50);
clear_bit(HID_RESUME_RUNNING, &usbhid->iofl);
Done:
mutex_unlock(&usbhid->mutex);
return res;

2
drivers/hid/usbhid/usbhid.h
View File

@ -13,6 +13,7 @@
#include <linux/types.h>
#include <linux/slab.h>
#include <linux/ktime.h>
#include <linux/list.h>
#include <linux/mutex.h>
#include <linux/timer.h>
@ -83,6 +84,7 @@ struct usbhid_device {
struct mutex mutex; /* start/stop/open/close */
spinlock_t lock; /* fifo spinlock */
unsigned long iofl; /* I/O flags (CTRL_RUNNING, OUT_RUNNING) */
ktime_t input_start_time; /* When to start handling input */
struct timer_list io_retry; /* Retry timer */
unsigned long stop_retry; /* Time to give up, in jiffies */
unsigned int retry_delay; /* Delay length in ms */