From f4e363ee29f2ac6bc94b29174be48eca761f540a Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Wed, 31 Jan 2024 14:36:52 -0500
Subject: [PATCH] XHCI: Report ring overrun/underrun (isochronous errors) back
 to drivers.

Since transfer status is reported via the packet descriptors, we
can report the endpoint status through the callback status.

Reduces syslog spam when using the USB audio driver.
---
 src/add-ons/kernel/busses/usb/xhci.cpp | 23 +++++++++++++++++++++--
 src/add-ons/kernel/busses/usb/xhci.h   |  1 +
 2 files changed, 22 insertions(+), 2 deletions(-)

diff --git a/src/add-ons/kernel/busses/usb/xhci.cpp b/src/add-ons/kernel/busses/usb/xhci.cpp
index 2fa4c81349..15035ba428 100644
--- a/src/add-ons/kernel/busses/usb/xhci.cpp
+++ b/src/add-ons/kernel/busses/usb/xhci.cpp
@@ -273,6 +273,10 @@ xhci_error_status(uint32 error, bool directionIn)
 			return directionIn ? B_DEV_WRITE_ERROR : B_DEV_READ_ERROR;
 		case COMP_BABBLE:
 			return directionIn ? B_DEV_DATA_OVERRUN : B_DEV_DATA_UNDERRUN;
+		case COMP_RING_UNDERRUN:
+			return B_DEV_FIFO_UNDERRUN;
+		case COMP_RING_OVERRUN:
+			return B_DEV_FIFO_OVERRUN;
 		case COMP_MISSED_SERVICE:
 			return B_DEV_TOO_LATE;
 		case COMP_USB_TRANSACTION:
@@ -1659,6 +1663,7 @@ XHCI::AllocateDevice(Hub *parent, int8 hubAddress, uint8 hubPort,
 	mutex_init(&endpoint0->lock, "xhci endpoint lock");
 	endpoint0->device = device;
 	endpoint0->id = 0;
+	endpoint0->status = 0;
 	endpoint0->td_head = NULL;
 	endpoint0->used = 0;
 	endpoint0->next = 0;
@@ -2641,7 +2646,15 @@ XHCI::HandleTransferComplete(xhci_trb* trb)
 	TRACE("HandleTransferComplete: ed %" B_PRIu32 ", status %" B_PRId32 "\n",
 		  (flags & TRB_3_EVENT_DATA_BIT), trb->status);
 
-	const uint8 completionCode = TRB_2_COMP_CODE_GET(trb->status);
+	uint8 completionCode = TRB_2_COMP_CODE_GET(trb->status);
+
+	if (completionCode == COMP_RING_OVERRUN || completionCode == COMP_RING_UNDERRUN) {
+		// These occur on isochronous endpoints when there is no TRB ready to be
+		// executed at the appropriate time. (XHCI 1.2 § 4.10.3.1 p204.)
+		endpoint->status = completionCode;
+		return;
+	}
+
 	int32 remainder = TRB_2_REM_GET(trb->status), transferred = -1;
 	if ((flags & TRB_3_EVENT_DATA_BIT) != 0) {
 		// In the case of an Event Data TRB, value in the status field refers
@@ -2707,6 +2720,12 @@ XHCI::HandleTransferComplete(xhci_trb* trb)
 				}
 				transferred += descriptor.actual_length;
 			}
+
+			// Report the endpoint status (if any.)
+			if (completionCode == COMP_SUCCESS && endpoint->status != 0) {
+				completionCode = endpoint->status;
+				endpoint->status = 0;
+			}
 		} else if (completionCode == COMP_STOPPED_LENGTH_INVALID) {
 			// To determine transferred length, sum up the lengths of all TRBs
 			// prior to the referenced one. (XHCI 1.2 § 4.6.9 p136.)
@@ -3130,7 +3149,7 @@ XHCI::FinishTransfers()
 					actualLength);
 			}
 
-			if (callbackStatus == B_OK && directionIn && actualLength > 0) {
+			if (directionIn && actualLength > 0) {
 				TRACE("copying in iov count %ld\n", transfer->VectorCount());
 				status_t status = transfer->PrepareKernelAccess();
 				if (status == B_OK) {
diff --git a/src/add-ons/kernel/busses/usb/xhci.h b/src/add-ons/kernel/busses/usb/xhci.h
index 47e51328c3..fbc7307331 100644
--- a/src/add-ons/kernel/busses/usb/xhci.h
+++ b/src/add-ons/kernel/busses/usb/xhci.h
@@ -55,6 +55,7 @@ typedef struct xhci_endpoint {
 
 	xhci_device*	device;
 	uint8			id;
+	uint8			status;
 
 	uint16			max_burst_payload;