4.9-stable review patch. If anyone has any objections, please let me know.
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From: Arnd Bergmann arnd@arndb.de
commit 7661ca09b2ff98f48693f431bb01fed62830e433 upstream.
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 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/usb/gadget/udc/dummy_hcd.c | 9 ++++----- 1 file changed, 4 insertions(+), 5 deletions(-)
--- a/drivers/usb/gadget/udc/dummy_hcd.c +++ b/drivers/usb/gadget/udc/dummy_hcd.c @@ -379,11 +379,10 @@ static void set_link_state_by_speed(stru 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 {