Currently VBUS is turned off while a usb device is detached, and turned on again by the polling routine. This short period VBUS loss prevents usb modem to switch mode. VBUS should be constantly on for host-only mode, so this changes the driver to not turn off VBUS for host-only mode. Fixes: 2f3fd2c5bde1 ("usb: musb: Prepare dsps glue layer for PM runtime support") Cc: stable@xxxxxxxxxxxxxxx #v4.11 Reported-by: Moreno Bartalucci <moreno.bartalucci@xxxxxxxxxxxx> Acked-by: Tony Lindgren <tony@xxxxxxxxxxx> Signed-off-by: Bin Liu <b-liu@xxxxxx> --- drivers/usb/musb/musb_dsps.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c index 9c7ee26ef388..bc6a9be2ccc5 100644 --- a/drivers/usb/musb/musb_dsps.c +++ b/drivers/usb/musb/musb_dsps.c @@ -245,6 +245,11 @@ static int dsps_check_status(struct musb *musb, void *unused) dsps_mod_timer_optional(glue); break; case OTG_STATE_A_WAIT_BCON: + /* keep VBUS on for host-only mode */ + if (musb->port_mode == MUSB_PORT_MODE_HOST) { + dsps_mod_timer_optional(glue); + break; + } musb_writeb(musb->mregs, MUSB_DEVCTL, 0); skip_session = 1; /* fall */ -- 1.9.1