From: Sebastian Andrzej Siewior Date: Mon, 27 Oct 2014 18:06:18 +0000 (+0100) Subject: usb: musb: core: check link status on resume X-Git-Tag: android-x86-4.4-r3~682^2~32^2~96 X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=b87fd2f7aa490a7f4bab44c41937aca0bc62fdc5;p=android-x86%2Fkernel.git usb: musb: core: check link status on resume The am335x-evmsk support two kinds of suspend: - standby the USB device remains powered while the system goes into suspend - mem the USB device becomes powerless while the system goes into suspend. In the "standby" case the device resumes quickly. In the "mem" case the system hangs for a few seconds. It seems to me that the USB-device has no address (it was disconnected) and the USB stack thinks that it is fully operational and GetPortStatus returns the status from before the suspend so it is not a big help here. This adds a check in the resume path to see if the device mode (A or B) and the speed is the same. If the device went missing between suspend/resume (VBUS went down) then MUSB seems to go into B mode and HS/FS bits are cleared. In that case we clear the port1_status bits and assume a disconnect. Once the stack learns this it does a "logical disconnect" and removes the USB-device quickly. Should the device remain connected during the suspend then MUSB will receives a "CONNECT" interrupt. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Felipe Balbi --- diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c index df9c5fa2772e..4966a166929a 100644 --- a/drivers/usb/musb/musb_core.c +++ b/drivers/usb/musb/musb_core.c @@ -2300,6 +2300,8 @@ static int musb_suspend(struct device *dev) static int musb_resume(struct device *dev) { struct musb *musb = dev_to_musb(dev); + u8 devctl; + u8 mask; /* * For static cmos like DaVinci, register values were preserved @@ -2313,6 +2315,10 @@ static int musb_resume(struct device *dev) musb_restore_context(musb); + devctl = musb_readb(musb->mregs, MUSB_DEVCTL); + mask = MUSB_DEVCTL_BDEVICE | MUSB_DEVCTL_FSDEV | MUSB_DEVCTL_LSDEV; + if ((devctl & mask) != (musb->context.devctl & mask)) + musb->port1_status = 0; return 0; }