remove shared usb mutex

src/main.zig

@@ -49,14 +49,12 @@ var slider_active = false;
 var slider_thread: ?std.Thread = null;
 var input_thread: ?std.Thread = null;
 
-var usb_op = std.Thread.Mutex{};
-var usb_in = std.mem.zeroes([0x24]u8);
+var usb_out_op = std.Thread.Mutex{};
 var usb_out = std.mem.zeroes([80*3]u8);
+var usb_in = std.mem.zeroes([0x24]u8);
 var tasoller: ?*anyopaque = null;
 
 fn tasoller_init() !void {
-    usb_op.lock();
-    defer usb_op.unlock();
 
     const hDevInfo = SetupDiGetClassDevsW(&GUID_DEVINTERFACE_USB_DEVICE, null, null, DIGCF_PRESENT | DIGCF_DEVICEINTERFACE);
     if(hDevInfo == INVALID_HANDLE_VALUE) {
@@ -123,12 +121,10 @@ fn tasoller_init() !void {
 // Poll input regardless of slider start/stop
 fn input_thread_proc() void {
     while(true) {
-        usb_op.lock();
         var len: u32 = 0;
         if(WinUsb_ReadPipe(tasoller, 0x84, @ptrCast(*u8, &usb_in), usb_in.len, &len, null) == 0) {
             std.log.warn("[chuniio] WinUsb_ReadPipe: {any}", .{GetLastError()});
         }
-        usb_op.unlock();
     }
 }
 
@@ -220,8 +216,8 @@ export fn chuni_io_slider_set_leds(rgb: ?[*]u8) void {
         out[n*3+2] = rgb.?[n*3+0];
     }
 
-    usb_op.lock();
-    defer usb_op.unlock();
+    usb_out_op.lock();
+    defer usb_out_op.unlock();
     if(WinUsb_WritePipe(tasoller, 0x03, @ptrCast(*u8, &usb_out), usb_out.len, &n, null) == 0) {
         std.log.warn("[chuniio] WinUsb_WritePipe: {any}", .{GetLastError()});
     }