[Qemu-devel] [PATCH v2] usb: reword -usb command-line option and mention xHCI

[Stefan Hajnoczi]

The -usb section of the man page is not very clear on what exactly -usb
does and fails to mention xHCI as a modern alternative (-device
nec-usb-xhci).

Signed-off-by: Stefan Hajnoczi <address@hidden>
---
v2:
 * Use @option{-device ...} [Thomas]
 * Suggest qemu-xhci instead of nec-usb-xhci [Thomas and David]
---
 qemu-options.hx | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/qemu-options.hx b/qemu-options.hx
index 9621e934c0..1fb362f06f 100644
--- a/qemu-options.hx
+++ b/qemu-options.hx
@@ -1436,12 +1436,15 @@ STEXI
 ETEXI
 
 DEF("usb", 0, QEMU_OPTION_usb,
-    "-usb            enable the USB driver (if it is not used by default 
yet)\n",
+    "-usb            enable on-board USB host controller (if not enabled by 
default)\n",
     QEMU_ARCH_ALL)
 STEXI
 @item -usb
 @findex -usb
-Enable the USB driver (if it is not used by default yet).
+Enable USB emulation on machine types with an on-board USB host controller (if
+not enabled by default).  Note that on-board USB host controllers may not
+support USB 3.0.  In this case @option{-device qemu-xhci} can be used instead
+on machines with PCI.
 ETEXI
 
 DEF("usbdevice", HAS_ARG, QEMU_OPTION_usbdevice,
-- 
2.21.0