<div dir="ltr"><div class="gmail_quote"><div dir="ltr" class="gmail_attr">Il giorno lun 21 nov 2022 alle ore 08:44 韩雪峰 <<a href="mailto:hanxuefeng@360.cn">hanxuefeng@360.cn</a>> ha scritto: </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg7338333656256773154"> <div lang="ZH-CN"> <div class="m_7338333656256773154WordSection1"> Hi, Thanks for your reply. But If I want to support multiple channels for USB redirection when multiple clients connect to a same VM, do you know which project includes the code about USB channels ? Spice ? or QEMU? Thanks and Regards, Xuefeng </div></div></div></blockquote><div> </div><div>Channels are a SPICE thing. But you will find surprisingly few code in SPICE (at least the server). The reason is that SPICE in this case mostly forwards data from/to usbredir (which is another project). In details Qemu uses usbredir to handle a USB device for the guest. This device is attached to spice-server which handles SPICE channels. A spice client (like spice-gtk) connects to SPICE USB channels and forward data from either a physical device or an emulated device (currently spice-gtk handles an emulated CD/DVD device).</div><div>Currently each SPICE USB channel is bound to a single Qemu device (I doubt it makes sense to bind it to multiple devices but it could in theory not be bound to a device).</div><div>Note that spice-server currently only forward data (presented like a pipe/stream) to/from client to the device, the hard lifting is made by Qemu/usbredir. </div><div> </div><div>Frediano </div><div> </div><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left:1px solid rgb(204,204,204);padding-left:1ex"><div class="msg7338333656256773154"><div lang="ZH-CN"><div class="m_7338333656256773154WordSection1"> 发件人: Frediano Ziglio <<a href="mailto:freddy77@gmail.com" target="_blank">freddy77@gmail.com</a>> 发送时间: 2022年11月18日 20:52 收件人: 韩雪峰 <<a href="mailto:hanxuefeng@360.cn" target="_blank">hanxuefeng@360.cn</a>> 抄送: <a href="mailto:spice-devel@lists.freedesktop.org" target="_blank">spice-devel@lists.freedesktop.org</a> 主题: Re: [Spice-devel] The second client cannot redirect USB <div> <div> <div> Il giorno ven 18 nov 2022 alle ore 10:21 韩雪峰 <<a href="mailto:hanxuefeng@360.cn" target="_blank">hanxuefeng@360.cn</a>> ha scritto: </div> <blockquote style="border-color:currentcolor currentcolor currentcolor rgb(204,204,204);border-style:none none none solid;border-width:medium medium medium 1pt;padding:0cm 0cm 0cm 6pt;margin-left:4.8pt;margin-right:0cm"> <div> <div> <div> Hello, When I used two client to connect to a same one VM by spice with setting “SPICE_DEBUG_ALLOW_MC=1”, the two clients worked, and the first client could redirect USB. However, the second client could not redirect USB device, It shows like the picture: <img style="width: 4.9479in; height: 2.6145in;" id="m_7338333656256773154m_4874315976305516369图片_x0020_1" src="cid:1849a2e634a4cff311" width="475" height="251" border="0"> I’m sure that there’re enough channels for USB redirection. Is this a problem? Or Is there any way that could resolve the second client’s USB redirection problem? Thanks and Regards, Xuefeng </div> </div> </div> </blockquote> <div> </div> <div> Currently all character device channels (including USB one) do not support multiple channels, so the first client takes them all. </div> <div> </div> <div> Frediano </div> </div> </div> </div> </div> </div></blockquote></div></div>