print messages with CMDDBG prefix if command ring is cleared
with pending commands, or fails to start due to sw state

TESTPATCH

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
---
 drivers/usb/host/xhci-ring.c |  5 ++++-
 drivers/usb/host/xhci.c      | 16 ++++++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index b9e676d37a33..f8029d837428 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -421,8 +421,11 @@ static unsigned int xhci_ring_expansion_needed(struct xhci_hcd *xhci, struct xhc
 /* Ring the host controller doorbell after placing a command on the ring */
 void xhci_ring_cmd_db(struct xhci_hcd *xhci)
 {
-	if (!(xhci->cmd_ring_state & CMD_RING_STATE_RUNNING))
+	if (!(xhci->cmd_ring_state & CMD_RING_STATE_RUNNING)) {
+		xhci_err(xhci, "%pS Failed to start cmd ring, sw cmd_ring_state %d\n",
+			 __builtin_return_address(0), xhci->cmd_ring_state);
 		return;
+	}
 
 	xhci_dbg(xhci, "// Ding dong!\n");
 
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index d3063f796130..fe157813c136 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -504,6 +504,14 @@ static void xhci_set_cmd_ring_deq(struct xhci_hcd *xhci)
 	dma_addr_t deq_dma;
 	u64 crcr;
 
+	if (!list_empty(&xhci->cmd_list))
+		xhci_err(xhci, "%pS CMDDBG set cmd ring deq pendig commands\n",
+			 __builtin_return_address(0));
+	if (xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue)
+		xhci_err(xhci,"%pS CMDDBG set cmd ring deq: %p and enq %p mismatch\n",
+			 __builtin_return_address(0),
+			 xhci->cmd_ring->dequeue, xhci->cmd_ring->enqueue);
+
 	deq_dma = xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg, xhci->cmd_ring->dequeue);
 	deq_dma &= CMD_RING_PTR_MASK;
 
@@ -871,6 +879,14 @@ static void xhci_clear_command_ring(struct xhci_hcd *xhci)
 	struct xhci_segment *seg;
 
 	ring = xhci->cmd_ring;
+
+	if (!list_empty(&xhci->cmd_list))
+		xhci_err(xhci, "CMDDBG Clearing command ring with pendig commands\n");
+
+	if (ring->dequeue != ring->enqueue)
+		xhci_err(xhci,"CMDDBG clear cmd ring deq: %p and enq %p mismatch\n",
+			 ring->dequeue, ring->enqueue);
+
 	xhci_for_each_ring_seg(ring->first_seg, seg) {
 		/* erase all TRBs before the link */
 		memset(seg->trbs, 0, sizeof(union xhci_trb) * (TRBS_PER_SEGMENT - 1));
-- 
2.43.0