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authorAlan Stern <stern@rowland.harvard.edu>2007-05-04 19:52:40 +0400
committerGreg Kroah-Hartman <gregkh@suse.de>2007-07-13 03:29:47 +0400
commit383975d765523a56dc43a6cd6d52e9b376800cf2 (patch)
treed6ecbfe620d7d5fba372211d7af185e7c44e5097 /drivers/usb/host/ohci-pci.c
parent0458d5b4c9cc4ca0f62625d0144ddc4b4bc97a3c (diff)
downloadlinux-383975d765523a56dc43a6cd6d52e9b376800cf2.tar.xz
USB: EHCI, OHCI: handover changes
This patch (as887) changes the way ehci-hcd and ohci-hcd handle a loss of VBUS power during suspend. In order for the USB-persist facility to work correctly, it is necessary for low- and full-speed devices attached to a high-speed port to be handed back to the companion controller during resume processing. This entails three changes: adding code to ehci-hcd to perform the handover, removing code from ohci-hcd to turn off ports during root-hub reinit, and adding code to ohci-hcd to turn on ports during PCI controller resume. (Other bus glue resume methods for platforms supporting high-speed controllers would need a similar change, if any existed.) Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/ohci-pci.c')
-rw-r--r--drivers/usb/host/ohci-pci.c41
1 files changed, 40 insertions, 1 deletions
diff --git a/drivers/usb/host/ohci-pci.c b/drivers/usb/host/ohci-pci.c
index ca62cb583221..15013f4519ad 100644
--- a/drivers/usb/host/ohci-pci.c
+++ b/drivers/usb/host/ohci-pci.c
@@ -202,6 +202,42 @@ static int __devinit ohci_pci_start (struct usb_hcd *hcd)
return ret;
}
+#if defined(CONFIG_USB_PERSIST) && (defined(CONFIG_USB_EHCI_HCD) || \
+ defined(CONFIG_USB_EHCI_HCD_MODULE))
+
+/* Following a power loss, we must prepare to regain control of the ports
+ * we used to own. This means turning on the port power before ehci-hcd
+ * tries to switch ownership.
+ *
+ * This isn't a 100% perfect solution. On most systems the OHCI controllers
+ * lie at lower PCI addresses than the EHCI controller, so they will be
+ * discovered (and hence resumed) first. But there is no guarantee things
+ * will always work this way. If the EHCI controller is resumed first and
+ * the OHCI ports are unpowered, then the handover will fail.
+ */
+static void prepare_for_handover(struct usb_hcd *hcd)
+{
+ struct ohci_hcd *ohci = hcd_to_ohci(hcd);
+ int port;
+
+ /* Here we "know" root ports should always stay powered */
+ ohci_dbg(ohci, "powerup ports\n");
+ for (port = 0; port < ohci->num_ports; port++)
+ ohci_writel(ohci, RH_PS_PPS,
+ &ohci->regs->roothub.portstatus[port]);
+
+ /* Flush those writes */
+ ohci_readl(ohci, &ohci->regs->control);
+ msleep(20);
+}
+
+#else
+
+static inline void prepare_for_handover(struct usb_hcd *hcd)
+{ }
+
+#endif /* CONFIG_USB_PERSIST etc. */
+
#ifdef CONFIG_PM
static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message)
@@ -241,7 +277,10 @@ static int ohci_pci_suspend (struct usb_hcd *hcd, pm_message_t message)
static int ohci_pci_resume (struct usb_hcd *hcd)
{
set_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags);
- usb_hcd_resume_root_hub(hcd);
+
+ /* FIXME: we should try to detect loss of VBUS power here */
+ prepare_for_handover(hcd);
+
return 0;
}