Lower the timer freq if no iso schedule packets complete for 64 frames in
a row.
We can safely do this, without adding latency, because:
1) If there is isoc traffic this will never trigger
2) For async handled interrupt packets (only usb-host), the completion handler
will immediately schedule the frame_timer from a bh
3) All devices using NAK to signal no data for interrupt endpoints now use
wakeup, which will immediately schedule the frame_timer from a bh
The advantage of this is that when we only have interrupt packets in the
periodic schedule, async_stepdown can do its work and significantly lower
the frequency at which the frame_timer runs.
Signed-off-by: Hans de Goede <hdego...@redhat.com>
---
hw/usb/hcd-ehci.c | 39 +++++++++++++++++++++++++++++++++------
hw/usb/hcd-ehci.h | 1 +
2 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/hw/usb/hcd-ehci.c b/hw/usb/hcd-ehci.c
index 7df8e21..7536837 100644
--- a/hw/usb/hcd-ehci.c
+++ b/hw/usb/hcd-ehci.c
@@ -114,6 +114,7 @@
#define BUFF_SIZE 5*4096 // Max bytes to transfer per transaction
#define MAX_QH 100 // Max allowable queue heads in a chain
#define MIN_FR_PER_TICK 3 // Min frames to process when catching up
+#define PERIODIC_ACTIVE 64
/* Internal periodic / asynchronous schedule state machine states
*/
@@ -738,6 +739,19 @@ static int ehci_register_companion(USBBus *bus, USBPort
*ports[],
return 0;
}
+static void ehci_wakeup_endpoint(USBBus *bus, USBEndpoint *ep)
+{
+ EHCIState *s = container_of(bus, EHCIState, bus);
+ uint32_t portsc = s->portsc[ep->dev->port->index];
+
+ if (portsc & PORTSC_POWNER) {
+ return;
+ }
+
+ s->periodic_sched_active = PERIODIC_ACTIVE;
+ qemu_bh_schedule(s->async_bh);
+}
+
static USBDevice *ehci_find_device(EHCIState *ehci, uint8_t addr)
{
USBDevice *dev;
@@ -1188,9 +1202,10 @@ static void ehci_async_complete_packet(USBPort *port,
USBPacket *packet)
trace_usb_ehci_packet_action(p->queue, p, "wakeup");
p->async = EHCI_ASYNC_FINISHED;
- if (p->queue->async) {
- qemu_bh_schedule(p->queue->ehci->async_bh);
+ if (!p->queue->async) {
+ s->periodic_sched_active = PERIODIC_ACTIVE;
}
+ qemu_bh_schedule(s->async_bh);
}
static void ehci_execute_complete(EHCIQueue *q)
@@ -1344,6 +1359,8 @@ static int ehci_process_itd(EHCIState *ehci,
uint32_t i, len, pid, dir, devaddr, endp;
uint32_t pg, off, ptr1, ptr2, max, mult;
+ ehci->periodic_sched_active = PERIODIC_ACTIVE;
+
dir =(itd->bufptr[1] & ITD_BUFPTR_DIRECTION);
devaddr = get_field(itd->bufptr[0], ITD_BUFPTR_DEVADDR);
endp = get_field(itd->bufptr[0], ITD_BUFPTR_EP);
@@ -2033,6 +2050,9 @@ static void ehci_advance_state(EHCIState *ehci, int async)
case EST_WRITEBACK:
assert(q != NULL);
again = ehci_state_writeback(q);
+ if (!async) {
+ ehci->periodic_sched_active = PERIODIC_ACTIVE;
+ }
break;
default:
@@ -2198,7 +2218,6 @@ static void ehci_frame_timer(void *opaque)
if (ehci_periodic_enabled(ehci) || ehci->pstate != EST_INACTIVE) {
need_timer++;
- ehci->async_stepdown = 0;
if (frames > ehci->maxframes) {
skipped_frames = frames - ehci->maxframes;
@@ -2222,18 +2241,25 @@ static void ehci_frame_timer(void *opaque)
break;
}
}
+ if (ehci->periodic_sched_active) {
+ ehci->periodic_sched_active--;
+ }
ehci_update_frindex(ehci, 1);
ehci_advance_periodic_state(ehci);
ehci->last_run_ns += FRAME_TIMER_NS;
}
} else {
- if (ehci->async_stepdown < ehci->maxframes / 2) {
- ehci->async_stepdown++;
- }
+ ehci->periodic_sched_active = 0;
ehci_update_frindex(ehci, frames);
ehci->last_run_ns += FRAME_TIMER_NS * frames;
}
+ if (ehci->periodic_sched_active) {
+ ehci->async_stepdown = 0;
+ } else if (ehci->async_stepdown < ehci->maxframes / 2) {
+ ehci->async_stepdown++;
+ }
+
/* Async is not inside loop since it executes everything it can once
* called
*/
@@ -2301,6 +2327,7 @@ static USBPortOps ehci_port_ops = {
static USBBusOps ehci_bus_ops = {
.register_companion = ehci_register_companion,
+ .wakeup_endpoint = ehci_wakeup_endpoint,
};
static int usb_ehci_post_load(void *opaque, int version_id)
diff --git a/hw/usb/hcd-ehci.h b/hw/usb/hcd-ehci.h
index d8078f4..772870b 100644
--- a/hw/usb/hcd-ehci.h
+++ b/hw/usb/hcd-ehci.h
@@ -311,6 +311,7 @@ struct EHCIState {
uint64_t last_run_ns;
uint32_t async_stepdown;
+ uint32_t periodic_sched_active;
bool int_req_by_async;
};
--
1.8.0
