USB: add flag for HCDs that can't receive wakeup requests (isp1760-hcd)

Currently the USB stack assumes that all host controller drivers are
capable of receiving wakeup requests from downstream devices.
However, this isn't true for the isp1760-hcd driver, which means that
it isn't safe to do a runtime suspend of any device attached to a
root-hub port if the device requires wakeup.

This patch adds a "cant_recv_wakeups" flag to the usb_hcd structure
and sets the flag in isp1760-hcd.  The core is modified to prevent a
direct child of the root hub from being put into runtime suspend with
wakeup enabled if the flag is set.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Tested-by: Nicolas Pitre <nico@linaro.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>

3 files changed, 17 insertions, 0 deletions

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index c76ec9758ce3..818369afff63 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1780,6 +1780,18 @@ static int autosuspend_check(struct usb_device *udev)
                 dev_dbg(&udev->dev, "remote wakeup needed for autosuspend\n");
                 return -EOPNOTSUPP;
         }
+
+        /*
+         * If the device is a direct child of the root hub and the HCD
+         * doesn't handle wakeup requests, don't allow autosuspend when
+         * wakeup is needed.
+         */
+        if (w && udev->parent == udev->bus->root_hub &&
+                        bus_to_hcd(udev->bus)->cant_recv_wakeups) {
+                dev_dbg(&udev->dev, "HCD doesn't handle wakeup requests\n");
+                return -EOPNOTSUPP;
+        }
+
         udev->do_remote_wakeup = w;
         return 0;
 }
diff --git a/drivers/usb/host/isp1760-hcd.c b/drivers/usb/host/isp1760-hcd.c
index dbba455884f4..cecf39a220e7 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -2245,6 +2245,9 @@ struct usb_hcd *isp1760_register(phys_addr_t res_start, resource_size_t res_len,
         hcd->rsrc_start = res_start;
         hcd->rsrc_len = res_len;
 
+        /* This driver doesn't support wakeup requests */
+        hcd->cant_recv_wakeups = 1;
+
         ret = usb_add_hcd(hcd, irq, irqflags);
         if (ret)
                 goto err_unmap;
diff --git a/include/linux/usb/hcd.h b/include/linux/usb/hcd.h
index 8968f616e414..68b1e836dff1 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -146,6 +146,8 @@ struct usb_hcd {
         unsigned                amd_resume_bug:1; /* AMD remote wakeup quirk */
         unsigned                can_do_streams:1; /* HC supports streams */
         unsigned                tpl_support:1; /* OTG & EH TPL support */
+        unsigned                cant_recv_wakeups:1;
+                        /* wakeup requests from downstream aren't received */
 
         unsigned int            irq;            /* irq allocated */
         void __iomem            *regs;          /* device memory/io */