From 7661ca09b2ff98f48693f431bb01fed62830e433 Mon Sep 17 00:00:00 2001
From: Arnd Bergmann <arnd@arndb.de>
Date: Thu, 7 Sep 2017 16:14:31 +0200
Subject: [PATCH] usb: gadget: dummy: fix nonsensical comparisons
Git-commit: 7661ca09b2ff98f48693f431bb01fed62830e433
Patch-mainline: v4.14-rc4
References: bsc#1051510

gcc-8 points out two comparisons that are clearly bogus
and almost certainly not what the author intended to write:

Drivers/usb/gadget/udc/dummy_hcd.c: In function 'set_link_state_by_speed':
drivers/usb/gadget/udc/dummy_hcd.c:379:31: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
         USB_PORT_STAT_ENABLE) == 1 &&
                               ^~
drivers/usb/gadget/udc/dummy_hcd.c:381:25: error: bitwise comparison always evaluates to false [-Werror=tautological-compare]
      USB_SS_PORT_LS_U0) == 1 &&
                         ^~

I looked at the code for a bit and came up with a change that makes
it look like what the author probably meant here. This makes it
look reasonable to me and to gcc, shutting up the warning.

It does of course change behavior as the two conditions are actually
evaluated rather than being hardcoded to false, and I have made no
attempt at verifying that the changed logic makes sense in the context
of a USB HCD, so that part needs to be reviewed carefully.

Fixes: 1cd8fd2887e1 ("usb: gadget: dummy_hcd: add SuperSpeed support")
Cc: Tatyana Brokhman <tlinder@codeaurora.org>
Cc: Felipe Balbi <balbi@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/usb/gadget/udc/dummy_hcd.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/gadget/udc/dummy_hcd.c b/drivers/usb/gadget/udc/dummy_hcd.c
index a030d7923d7d..b1e21b3be6e1 100644
--- a/drivers/usb/gadget/udc/dummy_hcd.c
+++ b/drivers/usb/gadget/udc/dummy_hcd.c
@@ -375,11 +375,10 @@ static void set_link_state_by_speed(struct dummy_hcd *dum_hcd)
 			     USB_PORT_STAT_CONNECTION) == 0)
 				dum_hcd->port_status |=
 					(USB_PORT_STAT_C_CONNECTION << 16);
-			if ((dum_hcd->port_status &
-			     USB_PORT_STAT_ENABLE) == 1 &&
-				(dum_hcd->port_status &
-				 USB_SS_PORT_LS_U0) == 1 &&
-				dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
+			if ((dum_hcd->port_status & USB_PORT_STAT_ENABLE) &&
+			    (dum_hcd->port_status &
+			     USB_PORT_STAT_LINK_STATE) == USB_SS_PORT_LS_U0 &&
+			    dum_hcd->rh_state != DUMMY_RH_SUSPENDED)
 				dum_hcd->active = 1;
 		}
 	} else {
-- 
2.18.0