Reject sample rates beyond 21.8 MHz.

Author: martinling

firmware/hackrf_usb/usb_api_transceiver.c

@@ -135,6 +135,11 @@ usb_request_status_t usb_vendor_request_set_sample_rate_frac(
 			NULL);
 		return USB_REQUEST_STATUS_OK;
 	} else if (stage == USB_TRANSFER_STAGE_DATA) {
+		float hz = (float) (set_sample_r_params.freq_hz) /
+			(float) set_sample_r_params.divider;
+		if (hz > 21800000.0) {
+			return USB_REQUEST_STATUS_STALL;
+		}
 		if (sample_rate_frac_set(
 			    set_sample_r_params.freq_hz * 2,
 			    set_sample_r_params.divider)) {