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authorMarcello Sylvester Bauer <sylv@sylv.io>2024-04-11 18:22:11 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-04-18 17:47:07 +0300
commit0a723ed3baa941ca4f51d87bab00661f41142835 (patch)
treec63bdd4268b8911f665d91ee85648f094d138bfd /drivers/usb/gadget
parenta7f3813e589fd8e2834720829a47b5eb914a9afe (diff)
downloadlinux-0a723ed3baa941ca4f51d87bab00661f41142835.tar.xz
usb: gadget: dummy_hcd: Set transfer interval to 1 microframe
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>
Diffstat (limited to 'drivers/usb/gadget')
-rw-r--r--drivers/usb/gadget/udc/dummy_hcd.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index dab559d8ee8c..f37b0d8386c1 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";
@@ -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 @@ return_urb:
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);