linux-kernel - [PATCH 3.16.y-ckt 064/183] USB: add flag for HCDs that can't receive wakeup requests (isp1760-hcd)

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Message-Id: <1425635874-19087-65-git-send-email-luis.henriques@canonical.com>
Date:	Fri,  6 Mar 2015 09:55:55 +0000
From:	Luis Henriques <luis.henriques@...onical.com>
To:	linux-kernel@...r.kernel.org, stable@...r.kernel.org,
	kernel-team@...ts.ubuntu.com
Cc:	Alan Stern <stern@...land.harvard.edu>,
	Greg Kroah-Hartman <greg@...ah.com>,
	Luis Henriques <luis.henriques@...onical.com>
Subject: [PATCH 3.16.y-ckt 064/183] USB: add flag for HCDs that can't receive wakeup requests (isp1760-hcd)

3.16.7-ckt8 -stable review patch.  If anyone has any objections, please let me know.

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

From: Alan Stern <stern@...land.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@...land.harvard.edu>
Tested-by: Nicolas Pitre <nico@...aro.org>
Signed-off-by: Greg Kroah-Hartman <greg@...ah.com>
[ luis: backported to 3.16: adjusted context ]
Signed-off-by: Luis Henriques <luis.henriques@...onical.com>
---
 drivers/usb/core/driver.c      | 12 ++++++++++++
 drivers/usb/host/isp1760-hcd.c |  3 +++
 include/linux/usb/hcd.h        |  2 ++
 3 files changed, 17 insertions(+)

diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
index 4aeb10034de7..37c7ce9af220 100644
--- a/drivers/usb/core/driver.c
+++ b/drivers/usb/core/driver.c
@@ -1800,6 +1800,18 @@ 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 51a0ae9cdd1d..5ea7c6bdfd28 100644
--- a/drivers/usb/host/isp1760-hcd.c
+++ b/drivers/usb/host/isp1760-hcd.c
@@ -2247,6 +2247,9 @@ 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 52598bdce2ba..6e98f62ea70d 100644
--- a/include/linux/usb/hcd.h
+++ b/include/linux/usb/hcd.h
@@ -144,6 +144,8 @@ struct usb_hcd {
 	unsigned		has_tt:1;	/* Integrated TT in root hub */
 	unsigned		amd_resume_bug:1; /* AMD remote wakeup quirk */
 	unsigned		can_do_streams:1; /* HC supports streams */
+	unsigned		cant_recv_wakeups:1;
+			/* wakeup requests from downstream aren't received */
 
 	unsigned int		irq;		/* irq allocated */
 	void __iomem		*regs;		/* device memory/io */
--
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