[PATCH 3.2 023/221] USB: add flag for HCDs that can't receive wakeup requests (isp1760-hcd)

Ben Hutchings
2015-05-05T01:53:41Z

From: Alan Stern <stern@rowland.harvard.edu>

commit 074f9dd55f9cab1b82690ed7e44bcf38b9616ce0 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/core/driver.c | 12 ++++++++++++
drivers/usb/host/isp1760-hcd.c | 3 +++
include/linux/usb/hcd.h | 2 ++
3 files changed, 17 insertions(+)

--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1664,6 +1664,18 @@ static int autosuspend_check(struct usb_
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;
}
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -2254,6 +2254,9 @@ struct usb_hcd *isp1760_register(phys_ad
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;
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -128,6 +128,8 @@ struct usb_hcd {
unsigned wireless:1; /* Wireless USB HCD */
unsigned authorized_default:1;
unsigned has_tt:1; /* Integrated TT in root hub */
+ unsigned cant_recv_wakeups:1;
+ /* wakeup requests from downstream aren't received */

int irq; /* irq allocated */
void __iomem *regs; /* device memory/io */