Michael and Anton:
Here is a preliminary patch meant to address the problem you have both
encountered: ATI's EHCI controller doesn't turn off the periodic
schedule as quickly as it should.
I wrote this patch against 3.2-rc5, but I think it will apply (perhaps
with minor changes) to any recent kernel. This isn't a complete
solution by any means; that will require a significantly larger change.
But I'd appreciate it if you can test this and see how well it does.
The patch adds a few ehci_info() calls, which will print some debugging
information in the system log. It will be interesting to see what
shows up.
Alan Stern
Index: usb-3.2/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-3.2.orig/drivers/usb/host/ehci-hcd.c
+++ usb-3.2/drivers/usb/host/ehci-hcd.c
@@ -361,6 +361,9 @@ static void ehci_quiesce (struct ehci_hc
BUG ();
#endif
+ ehci->periodic_timer_event = 0;
+ hrtimer_try_to_cancel(&ehci->hrtimer);
+
/* wait for any schedule enables/disables to take effect */
temp = ehci_readl(ehci, &ehci->regs->command) << 10;
temp &= STS_ASS | STS_PSS;
@@ -494,6 +497,9 @@ static void ehci_shutdown(struct usb_hcd
{
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
+ ehci->periodic_timer_event = 0;
+ hrtimer_cancel(&ehci->hrtimer);
+
del_timer_sync(&ehci->watchdog);
del_timer_sync(&ehci->iaa_watchdog);
@@ -562,6 +568,9 @@ static void ehci_stop (struct usb_hcd *h
ehci_dbg (ehci, "stop\n");
/* no more interrupts ... */
+ ehci->periodic_timer_event = 0;
+ hrtimer_cancel(&ehci->hrtimer);
+
del_timer_sync (&ehci->watchdog);
del_timer_sync(&ehci->iaa_watchdog);
@@ -621,6 +630,9 @@ static int ehci_init(struct usb_hcd *hcd
ehci->iaa_watchdog.function = ehci_iaa_watchdog;
ehci->iaa_watchdog.data = (unsigned long) ehci;
+ hrtimer_init(&ehci->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+ ehci->hrtimer.function = ehci_hrtimer_func;
+
hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
/*
@@ -952,6 +964,8 @@ static irqreturn_t ehci_irq (struct usb_
dbg_status(ehci, "fatal", status);
ehci_halt(ehci);
dead:
+ ehci->periodic_timer_event = 0;
+ hrtimer_try_to_cancel(&ehci->hrtimer);
ehci_reset(ehci);
ehci_writel(ehci, 0, &ehci->regs->configured_flag);
usb_hc_died(hcd);
Index: usb-3.2/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-3.2.orig/drivers/usb/host/ehci-hub.c
+++ usb-3.2/drivers/usb/host/ehci-hub.c
@@ -316,6 +316,9 @@ static int ehci_bus_suspend (struct usb_
if (ehci->reclaim)
end_unlink_async(ehci);
+ ehci->periodic_timer_event = 0;
+ hrtimer_try_to_cancel(&ehci->hrtimer);
+
/* allow remote wakeup */
mask = INTR_MASK;
if (!hcd->self.root_hub->do_remote_wakeup)
Index: usb-3.2/drivers/usb/host/ehci-sched.c
===================================================================
--- usb-3.2.orig/drivers/usb/host/ehci-sched.c
+++ usb-3.2/drivers/usb/host/ehci-sched.c
@@ -479,27 +479,103 @@ static int tt_no_collision (
/*-------------------------------------------------------------------------*/
-static int enable_periodic (struct ehci_hcd *ehci)
+static void send_command(struct ehci_hcd *ehci, u32 bit, int set)
{
- u32 cmd;
- int status;
+ ehci->command = ehci_readl(ehci, &ehci->regs->command);
+ if (set)
+ ehci->command |= bit;
+ else
+ ehci->command &= ~bit;
+ ehci_writel(ehci, ehci->command, &ehci->regs->command);
+ ehci_readl(ehci, &ehci->regs->command);
+ehci_info(ehci, "send command PSE %d\n", set);
+}
- if (ehci->periodic_sched++)
- return 0;
+#define EHCI_HRTIMER_PERIODIC_DISABLE 1
+#define EHCI_HRTIMER_PERIODIC_POLL 2
+
+static unsigned hrtimer_delays_ns[] = {
+ 0, /* dummy */
+ 10 * NSEC_PER_MSEC, /* wait before disabling periodic schedule */
+ 1 * NSEC_PER_MSEC, /* see if periodic schedule has stopped yet */
+};
+
+static void start_periodic_hrtimer(struct ehci_hcd *ehci, int event)
+{
+ unsigned delay_ns;
+
+ehci_info(ehci, "start hrtimer %d\n", event);
+ ehci->periodic_timer_event = event;
+ delay_ns = hrtimer_delays_ns[event];
+ ehci->periodic_timeout = ktime_add(ktime_get(), ktime_set(0, delay_ns));
+ hrtimer_start_range_ns(&ehci->hrtimer, ehci->periodic_timeout,
+ 125 * NSEC_PER_USEC, HRTIMER_MODE_ABS);
+}
+
+/* Wait until the periodic schedule stops, then restart it */
+static void poll_periodic_stop(struct ehci_hcd *ehci, ktime_t *now)
+{
+ u32 status;
- /* did clearing PSE did take effect yet?
- * takes effect only at frame boundaries...
- */
- status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
- STS_PSS, 0, 9 * 125);
- if (status) {
- usb_hc_died(ehci_to_hcd(ehci));
- return status;
+ status = ehci_readl(ehci, &ehci->regs->status);
+ if (unlikely(now && (status & STS_PSS))) {
+ if (ktime_us_delta(*now, ehci->periodic_disable_time)
+ > 20 * USEC_PER_MSEC) {
+ ehci_err(ehci, "Waited 20 ms for the periodic schedule to stop, giving up\n");
+ status = 0;
+ }
+ }
+ if (!(status & STS_PSS)) {
+ send_command(ehci, CMD_PSE, 1);
+ ehci->periodic_timer_event = 0;
+ } else if (!now) {
+ start_periodic_hrtimer(ehci, EHCI_HRTIMER_PERIODIC_POLL);
}
+}
+
+static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
+{
+ struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer);
+ ktime_t now = ktime_get();
- cmd = ehci_readl(ehci, &ehci->regs->command) | CMD_PSE;
- ehci_writel(ehci, cmd, &ehci->regs->command);
- /* posted write ... PSS happens later */
+ehci_info(ehci, "hrtimer func: event %d\n", ehci->periodic_timer_event);
+ if (ehci->periodic_timer_event == EHCI_HRTIMER_PERIODIC_DISABLE) {
+
+ /* Wait until time to disable the periodic schedule */
+ if (now.tv64 >= ehci->periodic_timeout.tv64) {
+ send_command(ehci, CMD_PSE, 0);
+ ehci->periodic_disable_time = ktime_get();
+ free_cached_lists(ehci);
+ ehci->periodic_timer_event = 0;
+ }
+
+ } else if (ehci->periodic_timer_event == EHCI_HRTIMER_PERIODIC_POLL) {
+ if (now.tv64 >= ehci->periodic_timeout.tv64)
+ poll_periodic_stop(ehci, &now);
+ }
+
+ if (ehci->periodic_timer_event) {
+ unsigned delay_ns;
+
+ delay_ns = hrtimer_delays_ns[ehci->periodic_timer_event];
+ hrtimer_forward_now(&ehci->hrtimer, ktime_set(0, delay_ns));
+ return HRTIMER_RESTART;
+ }
+ return HRTIMER_NORESTART;
+}
+
+static int enable_periodic (struct ehci_hcd *ehci)
+{
+ if (ehci->periodic_sched++)
+ return 0;
+
+ /* If we're still waiting to stop the periodic schedule, do nothing */
+ if (ehci->periodic_timer_event == EHCI_HRTIMER_PERIODIC_DISABLE)
+ ehci->periodic_timer_event = 0;
+
+ /* Otherwise, don't start until PSS is known to be 0 */
+ else
+ poll_periodic_stop(ehci, NULL);
/* make sure ehci_work scans these */
ehci->next_uframe = ehci_read_frame_index(ehci)
@@ -511,9 +587,6 @@ static int enable_periodic (struct ehci_
static int disable_periodic (struct ehci_hcd *ehci)
{
- u32 cmd;
- int status;
-
if (--ehci->periodic_sched)
return 0;
@@ -527,21 +600,13 @@ static int disable_periodic (struct ehci
udelay(delay);
}
- /* did setting PSE not take effect yet?
- * takes effect only at frame boundaries...
- */
- status = handshake_on_error_set_halt(ehci, &ehci->regs->status,
- STS_PSS, STS_PSS, 9 * 125);
- if (status) {
- usb_hc_died(ehci_to_hcd(ehci));
- return status;
- }
-
- cmd = ehci_readl(ehci, &ehci->regs->command) & ~CMD_PSE;
- ehci_writel(ehci, cmd, &ehci->regs->command);
- /* posted write ... */
-
- free_cached_lists(ehci);
+ /* If we're still waiting to start the periodic schedule, do nothing */
+ if (ehci->periodic_timer_event == EHCI_HRTIMER_PERIODIC_POLL)
+ ehci->periodic_timer_event = 0;
+
+ /* Otherwise wait for a while */
+ else
+ start_periodic_hrtimer(ehci, EHCI_HRTIMER_PERIODIC_DISABLE);
ehci->next_uframe = -1;
return 0;
Index: usb-3.2/drivers/usb/host/ehci.h
===================================================================
--- usb-3.2.orig/drivers/usb/host/ehci.h
+++ usb-3.2/drivers/usb/host/ehci.h
@@ -69,6 +69,11 @@ enum ehci_rh_state {
};
struct ehci_hcd { /* one per controller */
+ ktime_t periodic_timeout;
+ ktime_t periodic_disable_time;
+ struct hrtimer hrtimer;
+ int periodic_timer_event;
+
/* glue to PCI and HCD framework */
struct ehci_caps __iomem *caps;
struct ehci_regs __iomem *regs;
--
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