Hello Feng-Hsin Chiang, The patch 7d50195f6c50: "usb: host: Faraday fotg210-hcd driver" from Jul 29, 2013, leads to the following static checker warning: drivers/usb/host/fotg210-hcd.c:3967 iso_stream_init() warn: mask and shift to zero drivers/usb/host/fotg210-hcd.c 3944 static void iso_stream_init(struct fotg210_hcd *fotg210, 3945 struct fotg210_iso_stream *stream, struct usb_device *dev, 3946 int pipe, unsigned interval) 3947 { 3948 u32 buf1; 3949 unsigned epnum, maxp; 3950 int is_input; 3951 long bandwidth; 3952 unsigned multi; 3953 3954 /* 3955 * this might be a "high bandwidth" highspeed endpoint, 3956 * as encoded in the ep descriptor's wMaxPacket field 3957 */ 3958 epnum = usb_pipeendpoint(pipe); 3959 is_input = usb_pipein(pipe) ? USB_DIR_IN : 0; 3960 maxp = usb_maxpacket(dev, pipe, !is_input); 3961 if (is_input) 3962 buf1 = (1 << 11); 3963 else 3964 buf1 = 0; 3965 3966 maxp = max_packet(maxp); 3967 multi = hb_mult(maxp); "multi" is always one. max_packet() takes the lower 11 bits and hb_mult() shifts it to zero and adds one. Maybe introduce another variable or calculate hb_mult() before max_packet(). 3968 buf1 |= maxp; 3969 maxp *= multi; 3970 3971 stream->buf0 = cpu_to_hc32(fotg210, (epnum << 8) | dev->devnum); 3972 stream->buf1 = cpu_to_hc32(fotg210, buf1); 3973 stream->buf2 = cpu_to_hc32(fotg210, multi); regards, dan carpenter -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html