This is a note to let you know that I've just added the patch titled
usb: gadget: dummy_hcd: Set transfer interval to 1 microframe
to the 6.1-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
usb-gadget-dummy_hcd-set-transfer-interval-to-1-micr.patch
and it can be found in the queue-6.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 9d514adef89e7deb2adf6b0fd4b5c8f05b9101c4
Author: Marcello Sylvester Bauer <sylv@xxxxxxx>
Date: Thu Apr 11 17:22:11 2024 +0200
usb: gadget: dummy_hcd: Set transfer interval to 1 microframe
[ Upstream commit 0a723ed3baa941ca4f51d87bab00661f41142835 ]
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@xxxxxxxxxxxxx>
Signed-off-by: Marcello Sylvester Bauer <sylv@xxxxxxx>
Link: https://lore.kernel.org/r/6295dbb84ca76884551df9eb157cce569377a22c.1712843963.git.sylv@xxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index 4f9c6e86456fe..32a03de215d37 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -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";
@@ -1303,7 +1305,7 @@ 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);
@@ -1994,7 +1996,7 @@ 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);
