linux-kernel - [PATCH] usb: dwc2: host: Fix remote wakeup when not in DWC2

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Message-Id: <1445544303-24202-1-git-send-email-dianders@chromium.org>
Date:	Thu, 22 Oct 2015 13:05:03 -0700
From:	Douglas Anderson <dianders@...omium.org>
To:	John Youn <John.Youn@...opsys.com>, balbi@...com
Cc:	wulf@...k-chips.com, lyz@...k-chips.com, heiko@...ech.de,
	linux-rockchip@...ts.infradead.org,
	Julius Werner <jwerner@...omium.org>,
	gregory.herrero@...el.com, yousaf.kaukab@...el.com,
	r.baldyga@...sung.com, dinguyen@...nsource.altera.com,
	Douglas Anderson <dianders@...omium.org>,
	johnyoun@...opsys.com, gregkh@...uxfoundation.org,
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] usb: dwc2: host: Fix remote wakeup when not in DWC2_L2

In commit 734643dfbdde ("usb: dwc2: host: add flag to reflect bus
state") we changed dwc2_port_suspend() not to set the lx_state
anymore (instead it sets the new bus_suspended variable).  This
introduced a bug where we would fail to detect device insertions if:

1. Plug empty hub into dwc2
2. Plug USB flash drive into the empty hub.
3. Wait a few seconds
4. Unplug USB flash drive
5. Less than 2 seconds after step 4, plug the USB flash drive in again.

The dwc2_hcd_rem_wakeup() function should have been changed to look at
the new bus_suspended variable.

Let's fix it.  Since commit b46146d59fda ("usb: dwc2: host: resume root
hub on remote wakeup") talks about needing the root hub resumed if the
bus was suspended, we'll include it in our test.

It appears that the "port_l1_change" should only be set to 1 if we were
in DWC2_L1 (the driver currently never sets this), so we'll update the
former "else" case based on this test.

Fixes: 734643dfbdde ("usb: dwc2: host: add flag to reflect bus state")
Signed-off-by: Douglas Anderson <dianders@...omium.org>
---
 drivers/usb/dwc2/hcd.c | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/dwc2/hcd.c b/drivers/usb/dwc2/hcd.c
index e79baf73c234..571c21727ff9 100644
--- a/drivers/usb/dwc2/hcd.c
+++ b/drivers/usb/dwc2/hcd.c
@@ -324,12 +324,13 @@ void dwc2_hcd_disconnect(struct dwc2_hsotg *hsotg)
  */
 static void dwc2_hcd_rem_wakeup(struct dwc2_hsotg *hsotg)
 {
-	if (hsotg->lx_state == DWC2_L2) {
+	if (hsotg->bus_suspended) {
 		hsotg->flags.b.port_suspend_change = 1;
 		usb_hcd_resume_root_hub(hsotg->priv);
-	} else {
-		hsotg->flags.b.port_l1_change = 1;
 	}
+
+	if (hsotg->lx_state == DWC2_L1)
+		hsotg->flags.b.port_l1_change = 1;
 }

 /**
@@ -1428,8 +1429,8 @@ static void dwc2_wakeup_detected(unsigned long data)
 	dev_dbg(hsotg->dev, "Clear Resume: HPRT0=%0x\n",
 		dwc2_readl(hsotg->regs + HPRT0));

-	hsotg->bus_suspended = 0;
 	dwc2_hcd_rem_wakeup(hsotg);
+	hsotg->bus_suspended = 0;

 	/* Change to L0 state */
 	hsotg->lx_state = DWC2_L0;
-- 
2.6.0.rc2.230.g3dd15c0

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