From db360a206482811f67aaf677d49c675125c9079f Mon Sep 17 00:00:00 2001
From: Augustin Cavalier <waddlesplash@gmail.com>
Date: Mon, 18 Feb 2019 11:40:45 -0500
Subject: [PATCH] XHCI: Make sure we have at least one TRB in
 CreateDescriptorChain.

Linux seems to do the same thing. Confirmed as correct by korli
in #12929.
---
 src/add-ons/kernel/busses/usb/xhci.cpp | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/src/add-ons/kernel/busses/usb/xhci.cpp b/src/add-ons/kernel/busses/usb/xhci.cpp
index d816446318..7acc3914ff 100644
--- a/src/add-ons/kernel/busses/usb/xhci.cpp
+++ b/src/add-ons/kernel/busses/usb/xhci.cpp
@@ -883,6 +883,9 @@ XHCI::CreateDescriptorChain(size_t bufferSize, int32 &trbCount)
 {
 	size_t packetSize = B_PAGE_SIZE * 16;
 	trbCount = (bufferSize + packetSize - 1) / packetSize;
+	if (trbCount == 0)
+		trbCount = 1;
+
 	// keep one trb for linking
 	int32 tdCount = (trbCount + XHCI_MAX_TRBS_PER_TD - 2)
 		/ (XHCI_MAX_TRBS_PER_TD - 1);