Commit 499b3803 authored by Alan Stern's avatar Alan Stern Committed by Greg Kroah-Hartman
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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: default avatarAlan Stern <>
Tested-by: default avatarDennis New <>
Signed-off-by: default avatarGreg Kroah-Hartman <>
parent 81e38333
......@@ -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 @@ static int ohci_urb_enqueue (
/* Start up the I/O watchdog timer, if it's not running */
if (!timer_pending(&ohci->io_watchdog) &&
list_empty(&ohci->eds_in_use)) {
ohci->prev_frame_no = ohci_frame_no(ohci);
list_add(&ed->in_use_list, &ohci->eds_in_use);
if (ed->type == PIPE_ISOCHRONOUS) {
......@@ -727,6 +729,7 @@ static void io_watchdog_func(unsigned long _ohci)
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 @@ static void io_watchdog_func(unsigned long _ohci)
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");
......@@ -802,7 +806,35 @@ static void io_watchdog_func(unsigned long _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))
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,
......@@ -421,6 +421,7 @@ struct ohci_hcd {
// there are also chip quirks/bugs in init logic
unsigned prev_frame_no;
unsigned wdh_cnt, prev_wdh_cnt;
u32 prev_donehead;
struct timer_list io_watchdog;
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