Ok, i suppose you encountered the same issue i had months ago with other dual mayflash adapter on linux. To make sure, check if you have only js0 under /dev/input or if you also have js1

If you have only js0, then you have another adapter that uses the wrong kernel driver (it recognize both controllers as a unique controller with buttons x 2). You could solve this by modifying kernel sources then rebuild it, if it can help and if you some basic understanding of linux, patches and programming, here is a patch i wrote to fix this issue with my SS adapter and my PS adapter :

diff -git a/drivers/hid/hid-ids.h b/drivers/hid/hid-ids.h
--- a/drivers/hid/hid-ids.h
+++ b/drivers/hid/hid-ids.h
@@ -362,6 +362,8 @@
 
 #define USB_VENDOR_ID_GREENASIA		0x0e8f
 #define USB_DEVICE_ID_GREENASIA_DUAL_USB_JOYPAD	0x3013
+#define USB_DEVICE_ID_GREENASIA_DUAL_SS_JOYPAD 0x1006
+#define USB_DEVICE_ID_GREENASIA_DUAL_PS_JOYPAD 0x3010
 
 #define USB_VENDOR_ID_GRETAGMACBETH	0x0971
 #define USB_DEVICE_ID_GRETAGMACBETH_HUEY	0x2005
diff -git a/drivers/hid/usbhid/hid-quirks.c b/drivers/hid/usbhid/hid-quirks.c
--- a/drivers/hid/usbhid/hid-quirks.c
+++ b/drivers/hid/usbhid/hid-quirks.c
@@ -50,6 +50,8 @@ static const struct hid_blacklist {
 	{ USB_VENDOR_ID_EMS, USB_DEVICE_ID_EMS_TRIO_LINKER_PLUS_II, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_ETURBOTOUCH, USB_DEVICE_ID_ETURBOTOUCH, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_GREENASIA, USB_DEVICE_ID_GREENASIA_DUAL_USB_JOYPAD, HID_QUIRK_MULTI_INPUT },
+	{ USB_VENDOR_ID_GREENASIA, USB_DEVICE_ID_GREENASIA_DUAL_SS_JOYPAD, HID_QUIRK_MULTI_INPUT },
+	{ USB_VENDOR_ID_GREENASIA, USB_DEVICE_ID_GREENASIA_DUAL_PS_JOYPAD, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_PANTHERLORD, USB_DEVICE_ID_PANTHERLORD_TWIN_USB_JOYSTICK, HID_QUIRK_MULTI_INPUT | HID_QUIRK_SKIP_OUTPUT_REPORTS },
 	{ USB_VENDOR_ID_PLAYDOTCOM, USB_DEVICE_ID_PLAYDOTCOM_EMS_USBII, HID_QUIRK_MULTI_INPUT },
 	{ USB_VENDOR_ID_TOUCHPACK, USB_DEVICE_ID_TOUCHPACK_RTS, HID_QUIRK_MULTI_INPUT },

The 1006/3010 part is the id_product lsusb is returning.

The other (easier) solution is to not use autoconfig.