From: Ian Jackson <Ian.Jackson@eu.citrix.com>
To: Ian Campbell <ian.campbell@citrix.com>
Cc: Juergen Gross <jgross@suse.com>,
wei.liu2@citrix.com, george.dunlap@eu.citrix.com,
Ian.Jackson@eu.citrix.com, Chun Yan Liu <cyliu@suse.com>,
xen-devel@lists.xen.org, Jim Fehlig <JFEHLIG@suse.com>,
Simon Cao <caobosimon@gmail.com>
Subject: Re: [PATCH V6 3/7] libxl: add pvusb API
Date: Fri, 11 Sep 2015 16:42:15 +0100 [thread overview]
Message-ID: <22002.63063.974633.501641@mariner.uk.xensource.com> (raw)
In-Reply-To: <1441982504.3549.69.camel@citrix.com>
Most of what you say is right, I think, but:
Ian Campbell writes ("Re: [Xen-devel] [PATCH V6 3/7] libxl: add pvusb API"):
> On Fri, 2015-09-11 at 16:18 +0200, Juergen Gross wrote:
> > In theory I think up to 7 cascaded
> > hubs are possible, but I don't think the resulting theoretical maximum
> > of about 1 trillion devices on a bus is to be considered. :-)
>
> And this suggests that in principal a Linux hostbus could be 5*7 bits == 35
> bits, maybe. Or at least that any USB address can be encoded in that many
> bits.
No. The total possible number of `buses' in that sense
per root is:
1 root
+ 31 in theory a hub plugged into each of 31 ports
+ 31^2 in theory a hub plugged into each port
...
+ 31^6
You could plug hubs into the last layer but the maximum depth is 7 so
you wouldn't be able to plug any devices into that last hub.
And of course the number of root hubs is not really limited by
anything meaningful.
Ian.
next prev parent reply other threads:[~2015-09-11 15:42 UTC|newest]
Thread overview: 41+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-08-10 10:35 [PATCH V6 0/7] xen pvusb toolstack work Chunyan Liu
2015-08-10 10:35 ` [PATCH V6 1/7] libxl: export some functions for pvusb use Chunyan Liu
2015-08-11 11:26 ` Wei Liu
2015-08-10 10:35 ` [PATCH V6 2/7] libxl_read_file_contents: add new entry to read sysfs file Chunyan Liu
2015-08-11 11:26 ` Wei Liu
2015-08-12 2:37 ` Chun Yan Liu
2015-08-13 9:11 ` Wei Liu
2015-08-10 10:35 ` [PATCH V6 3/7] libxl: add pvusb API Chunyan Liu
2015-08-11 11:27 ` Wei Liu
2015-08-12 2:24 ` Chun Yan Liu
2015-08-13 9:09 ` Wei Liu
2015-08-14 1:49 ` Chun Yan Liu
2015-08-18 2:31 ` Chun Yan Liu
2015-08-31 6:10 ` Chun Yan Liu
2015-09-08 14:17 ` Ian Campbell
2015-09-08 16:52 ` George Dunlap
2015-09-09 7:38 ` Chun Yan Liu
2015-09-17 8:19 ` Chun Yan Liu
2015-09-17 9:54 ` George Dunlap
2015-09-29 17:19 ` Wei Liu
2015-09-17 8:20 ` Chun Yan Liu
2015-09-11 5:42 ` Chun Yan Liu
2015-09-11 13:26 ` Ian Campbell
2015-09-11 13:55 ` Juergen Gross
2015-09-11 14:09 ` Ian Campbell
2015-09-11 14:18 ` Juergen Gross
2015-09-11 14:41 ` Ian Campbell
2015-09-11 15:42 ` Ian Jackson [this message]
2015-09-14 3:48 ` Juergen Gross
2015-09-14 10:36 ` George Dunlap
2015-09-14 10:53 ` Juergen Gross
2015-09-14 11:12 ` Ian Jackson
2015-09-14 11:23 ` Juergen Gross
2015-09-14 14:03 ` George Dunlap
2015-09-17 8:24 ` Chun Yan Liu
2015-09-15 8:14 ` Chun Yan Liu
2015-08-10 10:35 ` [PATCH V6 4/7] libxl: add libxl_device_usb_assignable_list API Chunyan Liu
2015-08-10 10:35 ` [PATCH V6 5/7] xl: add pvusb commands Chunyan Liu
2015-08-10 10:35 ` [PATCH V6 6/7] xl: add usb-assignable-list command Chunyan Liu
2015-08-10 10:35 ` [PATCH V6 7/7] domcreate: support pvusb in configuration file Chunyan Liu
2015-08-11 11:27 ` Wei Liu
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=22002.63063.974633.501641@mariner.uk.xensource.com \
--to=ian.jackson@eu.citrix.com \
--cc=JFEHLIG@suse.com \
--cc=caobosimon@gmail.com \
--cc=cyliu@suse.com \
--cc=george.dunlap@eu.citrix.com \
--cc=ian.campbell@citrix.com \
--cc=jgross@suse.com \
--cc=wei.liu2@citrix.com \
--cc=xen-devel@lists.xen.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.