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path: root/drivers/usb/host/uhci-hcd.c
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Diffstat (limited to 'drivers/usb/host/uhci-hcd.c')
-rw-r--r--drivers/usb/host/uhci-hcd.c74
1 files changed, 58 insertions, 16 deletions
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index d3e0d8aa398..3a7bfe7a887 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -234,7 +234,7 @@ static int resume_detect_interrupts_are_broken(struct uhci_hcd *uhci)
return 0;
}
-static int remote_wakeup_is_broken(struct uhci_hcd *uhci)
+static int global_suspend_mode_is_broken(struct uhci_hcd *uhci)
{
int port;
const char *sys_info;
@@ -261,27 +261,60 @@ __releases(uhci->lock)
__acquires(uhci->lock)
{
int auto_stop;
- int int_enable, egsm_enable;
+ int int_enable, egsm_enable, wakeup_enable;
struct usb_device *rhdev = uhci_to_hcd(uhci)->self.root_hub;
auto_stop = (new_state == UHCI_RH_AUTO_STOPPED);
dev_dbg(&rhdev->dev, "%s%s\n", __func__,
(auto_stop ? " (auto-stop)" : ""));
- /* Enable resume-detect interrupts if they work.
- * Then enter Global Suspend mode if _it_ works, still configured.
+ /* Start off by assuming Resume-Detect interrupts and EGSM work
+ * and that remote wakeups should be enabled.
*/
egsm_enable = USBCMD_EGSM;
- uhci->working_RD = 1;
+ uhci->RD_enable = 1;
int_enable = USBINTR_RESUME;
- if (remote_wakeup_is_broken(uhci))
- egsm_enable = 0;
- if (resume_detect_interrupts_are_broken(uhci) || !egsm_enable ||
+ wakeup_enable = 1;
+
+ /* In auto-stop mode wakeups must always be detected, but
+ * Resume-Detect interrupts may be prohibited. (In the absence
+ * of CONFIG_PM, they are always disallowed.)
+ */
+ if (auto_stop) {
+ if (!device_may_wakeup(&rhdev->dev))
+ int_enable = 0;
+
+ /* In bus-suspend mode wakeups may be disabled, but if they are
+ * allowed then so are Resume-Detect interrupts.
+ */
+ } else {
#ifdef CONFIG_PM
- (!auto_stop && !rhdev->do_remote_wakeup) ||
+ if (!rhdev->do_remote_wakeup)
+ wakeup_enable = 0;
#endif
- (auto_stop && !device_may_wakeup(&rhdev->dev)))
- uhci->working_RD = int_enable = 0;
+ }
+
+ /* EGSM causes the root hub to echo a 'K' signal (resume) out any
+ * port which requests a remote wakeup. According to the USB spec,
+ * every hub is supposed to do this. But if we are ignoring
+ * remote-wakeup requests anyway then there's no point to it.
+ * We also shouldn't enable EGSM if it's broken.
+ */
+ if (!wakeup_enable || global_suspend_mode_is_broken(uhci))
+ egsm_enable = 0;
+
+ /* If we're ignoring wakeup events then there's no reason to
+ * enable Resume-Detect interrupts. We also shouldn't enable
+ * them if they are broken or disallowed.
+ *
+ * This logic may lead us to enabling RD but not EGSM. The UHCI
+ * spec foolishly says that RD works only when EGSM is on, but
+ * there's no harm in enabling it anyway -- perhaps some chips
+ * will implement it!
+ */
+ if (!wakeup_enable || resume_detect_interrupts_are_broken(uhci) ||
+ !int_enable)
+ uhci->RD_enable = int_enable = 0;
outw(int_enable, uhci->io_addr + USBINTR);
outw(egsm_enable | USBCMD_CF, uhci->io_addr + USBCMD);
@@ -308,7 +341,11 @@ __acquires(uhci->lock)
uhci->rh_state = new_state;
uhci->is_stopped = UHCI_IS_STOPPED;
- uhci_to_hcd(uhci)->poll_rh = !int_enable;
+
+ /* If interrupts don't work and remote wakeup is enabled then
+ * the suspended root hub needs to be polled.
+ */
+ uhci_to_hcd(uhci)->poll_rh = (!int_enable && wakeup_enable);
uhci_scan_schedule(uhci);
uhci_fsbr_off(uhci);
@@ -344,9 +381,12 @@ __acquires(uhci->lock)
* for 20 ms.
*/
if (uhci->rh_state == UHCI_RH_SUSPENDED) {
+ unsigned egsm;
+
+ /* Keep EGSM on if it was set before */
+ egsm = inw(uhci->io_addr + USBCMD) & USBCMD_EGSM;
uhci->rh_state = UHCI_RH_RESUMING;
- outw(USBCMD_FGR | USBCMD_EGSM | USBCMD_CF,
- uhci->io_addr + USBCMD);
+ outw(USBCMD_FGR | USBCMD_CF | egsm, uhci->io_addr + USBCMD);
spin_unlock_irq(&uhci->lock);
msleep(20);
spin_lock_irq(&uhci->lock);
@@ -801,8 +841,10 @@ static int uhci_pci_resume(struct usb_hcd *hcd)
spin_unlock_irq(&uhci->lock);
- if (!uhci->working_RD) {
- /* Suspended root hub needs to be polled */
+ /* If interrupts don't work and remote wakeup is enabled then
+ * the suspended root hub needs to be polled.
+ */
+ if (!uhci->RD_enable && hcd->self.root_hub->do_remote_wakeup) {
hcd->poll_rh = 1;
usb_hcd_poll_rh_status(hcd);
}