[PATCH 4.17 165/324] usb: xhci: dbc: Dont decrement runtime PM counter if DBC is not started

Greg Kroah-Hartman
2018-08-23T08:58:19Z

From: Kai-Heng Feng <kai.heng.feng@canonical.com>

[ Upstream commit 74cb319bd97dd62881f97ea5a3228f7c2546bf56 ]

pm_runtime_put_sync() gets called everytime in xhci_dbc_stop().

If dbc is not started, this makes the runtime PM counter incorrectly
becomes 0, and calls autosuspend function. Then we'll keep seeing this:
[54664.762220] xhci_hcd 0000:00:14.0: Root hub is not suspended

So only calls pm_runtime_put_sync() when dbc was started.

Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/usb/host/xhci-dbgcap.c | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/usb/host/xhci-dbgcap.c
+++ b/drivers/usb/host/xhci-dbgcap.c
@@ -507,16 +507,18 @@ static int xhci_do_dbc_start(struct xhci
return 0;
}

-static void xhci_do_dbc_stop(struct xhci_hcd *xhci)
+static int xhci_do_dbc_stop(struct xhci_hcd *xhci)
{
struct xhci_dbc *dbc = xhci->dbc;

if (dbc->state == DS_DISABLED)
- return;
+ return -1;

writel(0, &dbc->regs->control);
xhci_dbc_mem_cleanup(xhci);
dbc->state = DS_DISABLED;
+
+ return 0;
}

static int xhci_dbc_start(struct xhci_hcd *xhci)
@@ -543,6 +545,7 @@ static int xhci_dbc_start(struct xhci_hc

static void xhci_dbc_stop(struct xhci_hcd *xhci)
{
+ int ret;
unsigned long flags;
struct xhci_dbc *dbc = xhci->dbc;
struct dbc_port *port = &dbc->port;
@@ -555,10 +558,11 @@ static void xhci_dbc_stop(struct xhci_hc
xhci_dbc_tty_unregister_device(xhci);

spin_lock_irqsave(&dbc->lock, flags);
- xhci_do_dbc_stop(xhci);
+ ret = xhci_do_dbc_stop(xhci);
spin_unlock_irqrestore(&dbc->lock, flags);

- pm_runtime_put_sync(xhci_to_hcd(xhci)->self.controller);
+ if (!ret)
+ pm_runtime_put_sync(xhci_to_hcd(xhci)->self.controller);
}

static void