Every USB Host controller should use this new macro to define for how long resume signalling should be driven on the bus.
Currently, almost every single USB controller is using a 20ms timeout for resume signalling. That's problematic for two reasons: a) sometimes that 20ms timer expires a little before 20ms, which makes us fail certification b) some (many) devices actually need more than 20ms resume signalling. Sure, in case of (b) we can state that the device is against the USB spec, but the fact is that we have no control over which device the certification lab will use. We also have no control over which host they will use. Most likely they'll be using a Windows PC which, again, we have no control over how that USB stack is written and how long resume signalling they are using. At the end of the day, we must make sure Linux passes electrical compliance when working as Host or as Device and currently we don't pass compliance as host because we're driving resume signallig for exactly 20ms and that confuses certification test setup resulting in Certification failure. Signed-off-by: Felipe Balbi <ba...@ti.com> --- include/linux/usb.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/linux/usb.h b/include/linux/usb.h index f89c24a03bd9..1dd89f0db344 100644 --- a/include/linux/usb.h +++ b/include/linux/usb.h @@ -210,6 +210,9 @@ void usb_put_intf(struct usb_interface *intf); #define USB_MAXINTERFACES 32 #define USB_MAXIADS (USB_MAXINTERFACES/2) +/* USB Resume Timer */ +#define USB_RESUME_TIMEOUT 40 /* ms */ + /** * struct usb_interface_cache - long-term representation of a device interface * @num_altsetting: number of altsettings defined. -- 2.3.0 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
