suppress hid events from host when device is disconnected

.gitignore

@@ -1,2 +1,2 @@
-/build/**/*
-/external/**/*
+/*/**/*
+!/html/**/*

README.md

@@ -17,6 +17,8 @@ You will need the following hardware to make the device:
 - light dependent resistor such as GL5528 (specific part number may vary)
 - 10k ohm resistor (resistance value may vary)
 
+![Wiring schematic](schematic.svg)
+
 You will need to cut the USB extension in half and connect the wires from the
 female end to the Raspberry Pi Pico (2). The default configuration is to attach
 the USB's green wire to pin 1/GP0 and USB's white wire to pin 2/GP1. You will

hyperx_elite2.c

@@ -312,8 +312,6 @@ void parse_colors(char * data, uint16_t len) {
 	if (token != NULL) {
 		// first string is the RGB color code
 		uint8_t red, green, blue;
-		// sscanf(token, "%2x%2x%2x", &red, &green, &blue);
-		// sscanf causes Pico 1 to crash
 		red = hexbyte(token);
 		green = hexbyte(token+2);
 		blue = hexbyte(token+4);
@@ -362,6 +360,7 @@ void startADC() {
 
 // forward HID report after processing
 bool forward_report(uint8_t instance, uint8_t const* report, uint16_t len) {
+	if (device_state == DEVICE_ACTIVE ) {
 		if (instance == 0x01 && report[0] == 0x03 && report[1] == 0xE2) {
 			mute = !mute;
 		}
@@ -369,6 +368,9 @@ bool forward_report(uint8_t instance, uint8_t const* report, uint16_t len) {
 		return tud_hid_n_report(instance, 0, report, len);
 	}
 
+	return true;
+}
+
 // save RGB configuration to flash
 void save_rgb_config(void) {
 	// set save signature and number of bytes to be written into config

hyperx_elite2.h

@@ -196,5 +196,4 @@ bool load_rgb_config(void);
 	#error "Unsupported device. Expected RP2040 or RP2350."
 #endif
 
-
 #endif

usb_device.c

@@ -75,19 +75,17 @@ void usb_device_main(void) {
 	while (true) {
 		switch ( device_state ) {
 			case DEVICE_ACTIVE:
+				if (!tud_mounted()) {
+					device_state = DEVICE_INACTIVE;
+				}
 				break;
 			case DEVICE_INACTIVE:
 				break;
 			case DEVICE_RESTART:
 				if (tud_disconnect()) {
-					sleep_ms(10);
-					if (tud_connect()) {
-						if ( host_state == HOST_INACTIVE ) {
 					device_state = DEVICE_INACTIVE;
-						} else {
-							device_state = DEVICE_ACTIVE;
-						}
-					}
+					sleep_ms(10);
+					tud_connect();
 				}
 				break;
 			default:
@@ -214,7 +212,6 @@ uint8_t const * tud_hid_descriptor_report_cb(uint8_t itf)
 	return NULL;
 }
 
-
 // Invoked when received SET_REPORT control request or
 // received data on OUT endpoint ( Report ID = 0, Type = 0 )
 void tud_hid_set_report_cb(uint8_t instance, uint8_t report_id, hid_report_type_t report_type, uint8_t const* buffer, uint16_t bufsize) {
@@ -238,6 +235,11 @@ uint16_t tud_hid_get_report_cb(uint8_t instance, uint8_t report_id, hid_report_t
 	return 0;
 }
 
+// Invoked when device is mounted
+void tud_mount_cb(void) {
+	device_state = DEVICE_ACTIVE;
+}
+
 // print message to CDC in raw hex
 void cdc_print_hex(uint8_t const* msg, uint16_t msg_len) {
 	(void) msg;

usb_host.c

@@ -19,6 +19,7 @@ uint8_t num_mounted=0;
 static absolute_time_t request_time;
 static bool enabled=false;
 static uint8_t kb_addr=0;
+static struct hid_report last_report;
 
 static void usb_host_init(void);
 static void host_ready(void);
@@ -79,6 +80,22 @@ void usb_host_main(void) {
 				if (enabled) {
 					rgb_task(kb_addr);
 				}
+
+				if (last_report.len > 0 ) {
+					// previous report was not forwarded, resend
+					if ( forward_report(last_report.instance, last_report.report, last_report.len) ) {
+						// clear queue
+						last_report.len = 0;
+						memset(last_report.report, 0x00, REPORT_MAX_SIZE);
+
+						// continue requesting reports
+						if ( !tuh_hid_receive_report(last_report.dev_addr, last_report.instance) ) {
+							tud_cdc_write_str("Error: cannot request report\r\n");
+						}
+					} else {
+						tud_cdc_write_str("Error: failed resend report\r\n");
+					}
+				}
 				break;
 			default:
 				break;
@@ -142,14 +159,21 @@ void tuh_hid_report_received_cb(uint8_t dev_addr, uint8_t instance, uint8_t cons
 		cdc_print_hex(report, len);
 	}
 
-	forward_report(instance, report, len);
-
+	// forward report to device output
+	if ( !forward_report(instance, report, len) ) {
+		tud_cdc_write_str("Error: cannot forward report\r\n");
+		// queue report for resending
+		last_report.dev_addr = dev_addr;
+		last_report.instance = instance;
+		last_report.len = len;
+		memcpy(last_report.report, report, len);
+	} else {
 		// continue to request to receive report
-	if ( !tuh_hid_receive_report(dev_addr, instance) )
-	{
+		if ( !tuh_hid_receive_report(dev_addr, instance) ) {
 			tud_cdc_write_str("Error: cannot request report\r\n");
 		}
 	}
+}
 
 // start listening on host for HID events
 static void host_ready(void) {

usb_host.h

@@ -23,6 +23,13 @@ struct report_desc {
 	bool listening;
 };
 
+struct hid_report {
+	uint8_t dev_addr;
+	uint8_t instance;
+	uint16_t len;
+	uint8_t report[REPORT_MAX_SIZE];
+};
+
 #define REPORT_DESC_ALLOC() (struct report_desc *)malloc(sizeof(struct report_desc))
 
 extern host_state_t host_state;