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usb: gadget: dummy_hcd: Set transfer interval to 1 microframe

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Currently, the transfer polling interval is set to 1ms, which is the
frame rate of full-speed and low-speed USB. The USB 2.0 specification
introduces microframes (125 microseconds) to improve the timing
precision of data transfers.

Reducing the transfer interval to 1 microframe increases data throughput
for high-speed and super-speed USB communication

Signed-off-by: Marcello Sylvester Bauer <marcello.bauer@9elements.com>
Signed-off-by: Marcello Sylvester Bauer <sylv@sylv.io>
Link: https://lore.kernel.org/r/6295dbb84ca76884551df9eb157cce569377a22c.1712843963.git.sylv@sylv.io
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Marcello Sylvester Bauer 2024-04-11 17:22:11 +02:00 committed by Greg Kroah-Hartman
parent a7f3813e58
commit 0a723ed3ba
1 changed files with 4 additions and 2 deletions
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6
drivers/usb/gadget/udc/dummy_hcd.c
View File

@ -50,6 +50,8 @@
#define POWER_BUDGET 500 /* in mA; use 8 for low-power port testing */
#define POWER_BUDGET_3 900 /* in mA */
#define DUMMY_TIMER_INT_NSECS 125000 /* 1 microframe */
static const char driver_name[] = "dummy_hcd";
static const char driver_desc[] = "USB Host+Gadget Emulator";
@ -1302,7 +1304,7 @@ static int dummy_urb_enqueue(
/* kick the scheduler, it'll do the rest */
if (!hrtimer_active(&dum_hcd->timer))
hrtimer_start(&dum_hcd->timer, ms_to_ktime(1), HRTIMER_MODE_REL);
hrtimer_start(&dum_hcd->timer, ns_to_ktime(DUMMY_TIMER_INT_NSECS), HRTIMER_MODE_REL);
done:
spin_unlock_irqrestore(&dum_hcd->dum->lock, flags);
@ -1993,7 +1995,7 @@ static enum hrtimer_restart dummy_timer(struct hrtimer *t)
dum_hcd->udev = NULL;
} else if (dum_hcd->rh_state == DUMMY_RH_RUNNING) {
/* want a 1 msec delay here */
hrtimer_start(&dum_hcd->timer, ms_to_ktime(1), HRTIMER_MODE_REL);
hrtimer_start(&dum_hcd->timer, ns_to_ktime(DUMMY_TIMER_INT_NSECS), HRTIMER_MODE_REL);
}
spin_unlock_irqrestore(&dum->lock, flags);