usb: xhci: dbc: Don't decrement runtime PM counter if DBC is not started

BugLink: https://bugs.launchpad.net/bugs/1779823
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>
(cherry picked from commit 74cb319bd97dd62881f97ea5a3228f7c2546bf56 git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-linus)
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Acked-by: Po-Hsu Lin <po-hsu.lin@canonical.com>
Acked-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Kleber Sacilotto de Souza <kleber.souza@canonical.com>

diff --git a/drivers/usb/host/xhci-dbgcap.c b/drivers/usb/host/xhci-dbgcap.c
index 1fa4ca15779e946ad38e789cb9e3e2244b5ba469..3f32a0f8082fad2a1c68a8f03d0b88b804f15086 100644 (file)
--- 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_hcd *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_hcd *xhci)
 
 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_hcd *xhci)
                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