USB: OHCI: add check for stopped frame counter
This patch adds an extra check to ohci-hcd's I/O watchdog routine. If
the controller stops updating the frame counter, we will assume it is
dead. But there has to be an exception: Some controllers stop the
frame counter when no ports are connected. Check to make sure there
is at least one active port before deciding the controller is dead.
(This test may appear racy, but it isn't. Enabling a newly connected
port takes several milliseconds, during which time the frame counter
must advance.)
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Dennis New <dennisn@dennisn.linuxd.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/host/ohci-hcd.c b/drivers/usb/host/ohci-hcd.c
index aba8f19..4698773 100644
--- a/drivers/usb/host/ohci-hcd.c
+++ b/drivers/usb/host/ohci-hcd.c
@@ -72,7 +72,7 @@
static const char hcd_name [] = "ohci_hcd";
#define STATECHANGE_DELAY msecs_to_jiffies(300)
-#define IO_WATCHDOG_DELAY msecs_to_jiffies(250)
+#define IO_WATCHDOG_DELAY msecs_to_jiffies(250)
#include "ohci.h"
#include "pci-quirks.h"
@@ -230,9 +230,11 @@
/* Start up the I/O watchdog timer, if it's not running */
if (!timer_pending(&ohci->io_watchdog) &&
- list_empty(&ohci->eds_in_use))
+ list_empty(&ohci->eds_in_use)) {
+ ohci->prev_frame_no = ohci_frame_no(ohci);
mod_timer(&ohci->io_watchdog,
jiffies + IO_WATCHDOG_DELAY);
+ }
list_add(&ed->in_use_list, &ohci->eds_in_use);
if (ed->type == PIPE_ISOCHRONOUS) {
@@ -727,6 +729,7 @@
u32 head;
struct ed *ed;
struct td *td, *td_start, *td_next;
+ unsigned frame_no;
unsigned long flags;
spin_lock_irqsave(&ohci->lock, flags);
@@ -742,6 +745,7 @@
if (!(status & OHCI_INTR_WDH) && ohci->wdh_cnt == ohci->prev_wdh_cnt) {
if (ohci->prev_donehead) {
ohci_err(ohci, "HcDoneHead not written back; disabled\n");
+ died:
usb_hc_died(ohci_to_hcd(ohci));
ohci_dump(ohci);
ohci_shutdown(ohci_to_hcd(ohci));
@@ -802,7 +806,35 @@
ohci_work(ohci);
if (ohci->rh_state == OHCI_RH_RUNNING) {
+
+ /*
+ * Sometimes a controller just stops working. We can tell
+ * by checking that the frame counter has advanced since
+ * the last time we ran.
+ *
+ * But be careful: Some controllers violate the spec by
+ * stopping their frame counter when no ports are active.
+ */
+ frame_no = ohci_frame_no(ohci);
+ if (frame_no == ohci->prev_frame_no) {
+ int active_cnt = 0;
+ int i;
+ unsigned tmp;
+
+ for (i = 0; i < ohci->num_ports; ++i) {
+ tmp = roothub_portstatus(ohci, i);
+ /* Enabled and not suspended? */
+ if ((tmp & RH_PS_PES) && !(tmp & RH_PS_PSS))
+ ++active_cnt;
+ }
+
+ if (active_cnt > 0) {
+ ohci_err(ohci, "frame counter not updating; disabled\n");
+ goto died;
+ }
+ }
if (!list_empty(&ohci->eds_in_use)) {
+ ohci->prev_frame_no = frame_no;
ohci->prev_wdh_cnt = ohci->wdh_cnt;
ohci->prev_donehead = ohci_readl(ohci,
&ohci->regs->donehead);