[PATCH 3.4 017/172] USB: add flag for HCDs that can't receive wakeup requests (isp1760-hcd)

[lizf]

From: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>

3.4.108-rc1 review patch.  If anyone has any objections, please let me know.

------------------


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@xxxxxxxxxxxxxxxxxxx>
Tested-by: Nicolas Pitre <nico@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <greg@xxxxxxxxx>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
 drivers/usb/core/driver.c      | 12 ++++++++++++
 drivers/usb/host/isp1760-hcd.c |  3 +++
 include/linux/usb/hcd.h        |  1 +
 3 files changed, 16 insertions(+)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 35bc3ba..621ea00 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1686,6 +1686,18 @@ 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 fc72d44..949303f 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -2242,6 +2242,9 @@ 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 6674ec0..feb77716 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -126,6 +126,7 @@ 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;
 
 	unsigned int		irq;		/* irq allocated */
 	void __iomem		*regs;		/* device memory/io */
-- 
1.9.1

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