On Thu, 24 Jan 2013, Ming Lei wrote:
> > What we really want to do is prevent the root hub from autosuspending
> > while the resume signal is active. One possibility is to have the HCD
> > call pm_runtime_get_noresume. Can you think of anything better?
>
> pm_runtime_get_noresume should be better than adjusting autosuspend
> delay, but the 'suspend failed' message can't be avoided. Or could we
> schedule a delayed work to handle hub_activate(HUB_RESUME) for
> the case?
Here's my first attempt. I have not tested it yet.
Alan Stern
drivers/usb/core/hcd.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
include/linux/usb.h | 2 ++
include/linux/usb/hcd.h | 3 +++
3 files changed, 49 insertions(+)
Index: usb-3.8/include/linux/usb.h
===================================================================
--- usb-3.8.orig/include/linux/usb.h
+++ usb-3.8/include/linux/usb.h
@@ -357,6 +357,8 @@ struct usb_bus {
int bandwidth_int_reqs; /* number of Interrupt requests */
int bandwidth_isoc_reqs; /* number of Isoc. requests */
+ unsigned resuming_ports; /* bit array: resuming root-hub ports */
+
#if defined(CONFIG_USB_MON) || defined(CONFIG_USB_MON_MODULE)
struct mon_bus *mon_bus; /* non-null when associated */
int monitored; /* non-zero when monitored */
Index: usb-3.8/include/linux/usb/hcd.h
===================================================================
--- usb-3.8.orig/include/linux/usb/hcd.h
+++ usb-3.8/include/linux/usb/hcd.h
@@ -430,6 +430,9 @@ extern void usb_hcd_poll_rh_status(struc
extern void usb_wakeup_notification(struct usb_device *hdev,
unsigned int portnum);
+extern void usb_hcd_start_port_resume(struct usb_bus *bus, int portnum);
+extern void usb_hcd_end_port_resume(struct usb_bus *bus, int portnum);
+
/* The D0/D1 toggle bits ... USE WITH CAUTION (they're almost hcd-internal) */
#define usb_gettoggle(dev, ep, out) (((dev)->toggle[out] >> (ep)) & 1)
#define usb_dotoggle(dev, ep, out) ((dev)->toggle[out] ^= (1 << (ep)))
Index: usb-3.8/drivers/usb/core/hcd.c
===================================================================
--- usb-3.8.orig/drivers/usb/core/hcd.c
+++ usb-3.8/drivers/usb/core/hcd.c
@@ -39,6 +39,7 @@
#include <asm/unaligned.h>
#include <linux/platform_device.h>
#include <linux/workqueue.h>
+#include <linux/pm_runtime.h>
#include <linux/usb.h>
#include <linux/usb/hcd.h>
@@ -1029,6 +1030,49 @@ static int register_root_hub(struct usb_
return retval;
}
+/*
+ * usb_hcd_start_port_resume - a root-hub port is sending a resume signal
+ * @bus: the bus which the root hub belongs to
+ * @portnum: the port which is being resumed
+ *
+ * HCDs should call this function when they know that a resume signal is
+ * being sent to a root-hub port. The root hub will be prevented from
+ * going into autosuspend until usb_hcd_end_port_resume() is called.
+ *
+ * The bus's private lock must be held by the caller.
+ */
+void usb_hcd_start_port_resume(struct usb_bus *bus, int portnum)
+{
+ unsigned bit = 1 << portnum;
+
+ if (!(bus->resuming_ports & bit)) {
+ bus->resuming_ports |= bit;
+ pm_runtime_get_noresume(&bus->root_hub->dev);
+ }
+}
+EXPORT_SYMBOL_GPL(usb_hcd_start_port_resume);
+
+/*
+ * usb_hcd_end_port_resume - a root-hub port has stopped sending a resume signal
+ * @bus: the bus which the root hub belongs to
+ * @portnum: the port which is being resumed
+ *
+ * HCDs should call this function when they know that a resume signal has
+ * stopped being sent to a root-hub port. The root hub will be allowed to
+ * autosuspend again.
+ *
+ * The bus's private lock must be held by the caller.
+ */
+void usb_hcd_end_port_resume(struct usb_bus *bus, int portnum)
+{
+ unsigned bit = 1 << portnum;
+
+ if (bus->resuming_ports & bit) {
+ bus->resuming_ports &= ~bit;
+ pm_runtime_put_noidle(&bus->root_hub->dev);
+ }
+}
+EXPORT_SYMBOL_GPL(usb_hcd_end_port_resume);
/*-------------------------------------------------------------------------*/
Index: usb-3.8/drivers/usb/host/ehci-hcd.c
===================================================================
--- usb-3.8.orig/drivers/usb/host/ehci-hcd.c
+++ usb-3.8/drivers/usb/host/ehci-hcd.c
@@ -797,6 +797,7 @@ static irqreturn_t ehci_irq (struct usb_
ehci->reset_done[i] = jiffies + msecs_to_jiffies(25);
set_bit(i, &ehci->resuming_ports);
ehci_dbg (ehci, "port %d remote wakeup\n", i + 1);
+ usb_hcd_start_port_resume(&hcd->self, i);
mod_timer(&hcd->rh_timer, ehci->reset_done[i]);
}
}
Index: usb-3.8/drivers/usb/host/ehci-hub.c
===================================================================
--- usb-3.8.orig/drivers/usb/host/ehci-hub.c
+++ usb-3.8/drivers/usb/host/ehci-hub.c
@@ -855,6 +855,7 @@ static int ehci_hub_control (
/* resume signaling for 20 msec */
ehci->reset_done[wIndex] = jiffies
+ msecs_to_jiffies(20);
+ usb_hcd_start_port_resume(&hcd->self, wIndex);
/* check the port again */
mod_timer(&ehci_to_hcd(ehci)->rh_timer,
ehci->reset_done[wIndex]);
@@ -866,6 +867,7 @@ static int ehci_hub_control (
clear_bit(wIndex, &ehci->suspended_ports);
set_bit(wIndex, &ehci->port_c_suspend);
ehci->reset_done[wIndex] = 0;
+ usb_hcd_end_port_resume(&hcd->self, wIndex);
/* stop resume signaling */
temp = ehci_readl(ehci, status_reg);
@@ -954,6 +956,7 @@ static int ehci_hub_control (
ehci->reset_done[wIndex] = 0;
if (temp & PORT_PE)
set_bit(wIndex, &ehci->port_c_suspend);
+ usb_hcd_end_port_resume(&hcd->self, wIndex);
}
if (temp & PORT_OC)
--
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