systemtap test

usb.stp

#!/usr/bin/stap -gv

probe begin {
    printf("force stop warning short TX\n")
}

probe end {
    printf("stop probe\n")
}

global changed = 0
probe kernel.statement("handle_tx_event@drivers/usb/host/xhci-ring.c:2380") {
    $xhci->quirks = $xhci->quirks | (1 << 10) # XHCI_TRUST_TX_LENGTH = (1<<10)
    changed = 1
    # printf("NO QUIRK OK\n");
}

global g_trb_comp_code = 0
probe kernel.statement("handle_tx_event@drivers/usb/host/xhci-ring.c:2477") {
    if(changed) {
        changed = 0
        $trb_comp_code = 1
    }
    next_addr = @cast(&$ep_ring->td_list, "list_head", "kernel")->next
    list_addr = &$ep_ring->td_list
    if(next_addr == list_addr) {
        g_trb_comp_code = $trb_comp_code
        $trb_comp_code = 26 # COMP_STOP
    }

}

probe kernel.statement("handle_tx_event@drivers/usb/host/xhci-ring.c:2493") {
    if(g_trb_comp_code) {
        $trb_comp_code = g_trb_comp_code
        g_trb_comp_code = 0
    }
}