check that boot device is interface #0; remove instrumentation

locale/circuitpython.pot

@@ -551,6 +551,10 @@ msgstr ""
 msgid "Bit depth must be multiple of 8."
 msgstr ""
 
+#: supervisor/shared/safe_mode.c
+msgid "Boot device must be first device (interface #0)."
+msgstr ""
+
 #: ports/mimxrt10xx/common-hal/busio/UART.c
 msgid "Both RX and TX required for flow control"
 msgstr ""

shared-bindings/microcontroller/Processor.c

@@ -97,9 +97,8 @@ const mp_obj_property_t mcu_processor_reset_reason_obj = {
 //|
 //|     Is `None` if the temperature is not available."""
 //|
-extern volatile float indicator;
 STATIC mp_obj_t mcu_processor_get_temperature(mp_obj_t self) {
-    float temperature = indicator; // common_hal_mcu_processor_get_temperature();
+    float temperature = common_hal_mcu_processor_get_temperature();
     return isnan(temperature) ? mp_const_none : mp_obj_new_float(temperature);
 }
 

shared-bindings/usb_hid/__init__.c

@@ -100,6 +100,12 @@ MP_DEFINE_CONST_FUN_OBJ_0(usb_hid_disable_obj, usb_hid_disable);
 //|     will be ignored, and the predefined report descriptor will be used.
 //|     But if the host does not request the boot keyboard,
 //|     the descriptor provided by `Device.KEYBOARD` will be used.
+//|
+//|     The HID boot device must usually be the first or only device presented by CircuitPython.
+//|     The HID device will be USB interface number 0.
+//|     To make sure it is the first device, disable other USB devices, including CDC and MSC (CIRCUITPY).
+//|     If you specify a non-zero ``boot_device``, and it is not the first device, CircuitPython
+//|     will enter safe mode to report this error.
 //|     """
 //|     ...
 //|

shared-module/usb_hid/__init__.c

@@ -35,8 +35,6 @@
 #include "supervisor/memory.h"
 #include "supervisor/usb.h"
 
-volatile float indicator = 0.1f;
-
 static const uint8_t usb_hid_descriptor_template[] = {
     0x09,        //  0 bLength
     0x04,        //  1 bDescriptorType (Interface)
@@ -85,10 +83,9 @@ static usb_hid_device_obj_t hid_devices[MAX_HID_DEVICES];
 // If 0, USB HID is disabled.
 static mp_int_t num_hid_devices;
 
-// Which boot device is available 0: no boot devices, 1: boot keyboard, 2: boot mouse.
+// Which boot device is available? 0: no boot devices, 1: boot keyboard, 2: boot mouse.
 // This value is set by usb_hid.enable(), and used to build the HID interface descriptor.
 // The value is remembered here from boot.py to code.py.
-
 static uint8_t hid_boot_device;
 
 // Whether a boot device was requested by a SET_PROTOCOL request from the host.

supervisor/shared/safe_mode.c

@@ -169,6 +169,9 @@ void print_safe_mode_message(safe_mode_t reason) {
         case USB_TOO_MANY_INTERFACE_NAMES:
             message = translate("USB devices specify too many interface names.");
             break;
+        case USB_BOOT_DEVICE_NOT_INTERFACE_ZERO:
+            message = translate("Boot device must be first device (interface #0).");
+            break;
         case WATCHDOG_RESET:
             message = translate("Watchdog timer expired.");
             break;

supervisor/shared/safe_mode.h

@@ -46,6 +46,7 @@ typedef enum {
     WATCHDOG_RESET,
     USB_TOO_MANY_ENDPOINTS,
     USB_TOO_MANY_INTERFACE_NAMES,
+    USB_BOOT_DEVICE_NOT_INTERFACE_ZERO,
     NO_HEAP,
 } safe_mode_t;
 

supervisor/shared/usb/usb_desc.c

@@ -228,6 +228,11 @@ static void usb_build_configuration_descriptor(void) {
 
     #if CIRCUITPY_USB_HID
     if (usb_hid_enabled()) {
+        if (usb_hid_boot_device() > 0 && descriptor_counts.current_interface > 0) {
+            // Hosts using boot devices generally to expect them to be at interface zero,
+            // and will not work properly otherwise.
+            reset_into_safe_mode(USB_BOOT_DEVICE_NOT_INTERFACE_ZERO);
+        }
         descriptor_buf_remaining += usb_hid_add_descriptor(
             descriptor_buf_remaining, &descriptor_counts, &current_interface_string,
             usb_hid_report_descriptor_length(), usb_hid_boot_device());