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authorPeter Maydell <peter.maydell@linaro.org>2022-07-19 17:40:36 +0100
committerPeter Maydell <peter.maydell@linaro.org>2022-07-19 17:40:36 +0100
commitd48125de38f48a61d6423ef6a01156d6dff9ee2c (patch)
treef1555f3565dcb7f00a4ba7a6b581700516b720a6 /docs
parentda7da9d5e608200ecc0749ff37be246e9cd3314f (diff)
parentc34a933802071aae5288e0aa3792756312e3da34 (diff)
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Merge tag 'kraxel-20220719-pull-request' of https://gitlab.com/kraxel/qemu into staging
ui: dbus-display fix, new gtk config options. usb: xhci fix, doc updates. microvm: no pcie io reservations. # gpg: Signature made Tue 19 Jul 2022 16:21:06 BST # gpg: using RSA key A0328CFFB93A17A79901FE7D4CB6D8EED3E87138 # gpg: Good signature from "Gerd Hoffmann (work) <kraxel@redhat.com>" [full] # gpg: aka "Gerd Hoffmann <gerd@kraxel.org>" [full] # gpg: aka "Gerd Hoffmann (private) <kraxel@gmail.com>" [full] # Primary key fingerprint: A032 8CFF B93A 17A7 9901 FE7D 4CB6 D8EE D3E8 7138 * tag 'kraxel-20220719-pull-request' of https://gitlab.com/kraxel/qemu: gtk: Add show_tabs=on|off command line option. usb: document pcap (aka usb traffic capture) usb: document guest-reset and guest-reset-all usb/hcd-xhci: check slotid in xhci_wakeup_endpoint() microvm: turn off io reservations for pcie root ports dbus-display: fix test race when initializing p2p connection Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'docs')
-rw-r--r--docs/system/devices/usb.rst41
1 files changed, 41 insertions, 0 deletions
diff --git a/docs/system/devices/usb.rst b/docs/system/devices/usb.rst
index 872d916..f39a88f 100644
--- a/docs/system/devices/usb.rst
+++ b/docs/system/devices/usb.rst
@@ -353,3 +353,44 @@ and also assign it to the correct USB bus in QEMU like this:
-device usb-ehci,id=ehci \\
-device usb-host,bus=usb-bus.0,hostbus=3,hostport=1 \\
-device usb-host,bus=ehci.0,hostbus=1,hostport=1
+
+``usb-host`` properties for reset behavior
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
+
+The ``guest-reset`` and ``guest-reset-all`` properties control
+whenever the guest is allowed to reset the physical usb device on the
+host. There are three cases:
+
+``guest-reset=false``
+ The guest is not allowed to reset the (physical) usb device.
+
+``guest-reset=true,guest-resets-all=false``
+ The guest is allowed to reset the device when it is not yet
+ initialized (aka no usb bus address assigned). Usually this results
+ in one guest reset being allowed. This is the default behavior.
+
+``guest-reset=true,guest-resets-all=true``
+ The guest is allowed to reset the device as it pleases.
+
+The reason for this existing are broken usb devices. In theory one
+should be able to reset (and re-initialize) usb devices at any time.
+In practice that may result in shitty usb device firmware crashing and
+the device not responding any more until you power-cycle (aka un-plug
+and re-plug) it.
+
+What works best pretty much depends on the behavior of the specific
+usb device at hand, so it's a trial-and-error game. If the default
+doesn't work, try another option and see whenever the situation
+improves.
+
+record usb transfers
+^^^^^^^^^^^^^^^^^^^^
+
+All usb devices have support for recording the usb traffic. This can
+be enabled using the ``pcap=<file>`` property, for example:
+
+``-device usb-mouse,pcap=mouse.pcap``
+
+The pcap files are compatible with the linux kernels usbmon. Many
+tools, including ``wireshark``, can decode and inspect these trace
+files.