From owner-freebsd-usb@freebsd.org Thu May 2 08:31:15 2019 Return-Path: Delivered-To: freebsd-usb@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 00B75158D1F4 for ; Thu, 2 May 2019 08:31:15 +0000 (UTC) (envelope-from darius@dons.net.au) Received: from ipmail07.adl2.internode.on.net (ipmail07.adl2.internode.on.net [150.101.137.131]) by mx1.freebsd.org (Postfix) with ESMTP id 6991883939 for ; Thu, 2 May 2019 08:31:10 +0000 (UTC) (envelope-from darius@dons.net.au) Received: from unknown (HELO midget.dons.net.au) ([118.211.90.89]) by ipmail07.adl2.internode.on.net with ESMTP; 02 May 2019 18:00:59 +0930 Received: from midget.dons.net.au (localhost [127.0.0.1]) by midget.dons.net.au (8.15.2/8.15.2) with ESMTPS id x428UhBG036952 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO) for ; Thu, 2 May 2019 18:00:53 +0930 (ACST) (envelope-from darius@dons.net.au) Received: (from mailnull@localhost) by midget.dons.net.au (8.15.2/8.15.2/Submit) id x428MBgg029848 for ; Thu, 2 May 2019 17:52:11 +0930 (ACST) (envelope-from darius@dons.net.au) X-Authentication-Warning: midget.dons.net.au: mailnull set sender to using -f Received: from [203.31.81.59] ([203.31.81.59]) by [118.211.90.89] (envelope-sender ) (MIMEDefang) with ESMTP id x428M671029846; Thu, 02 May 2019 17:52:11 +0930 Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: USB transfers in device drivers From: "O'Connor, Daniel" In-Reply-To: Date: Thu, 2 May 2019 17:52:05 +0930 Cc: freebsd-usb@freebsd.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <3B922C60-32E5-484E-8AFA-28FF7255CF2C@dons.net.au> To: Hans Petter Selasky X-Mailer: Apple Mail (2.3445.104.8) X-Spam-Score: 1.3 (*) No, score=1.3 required=5.0 tests=RDNS_NONE autolearn=no autolearn_force=no version=3.4.1 X-Scanned-By: MIMEDefang 2.83 on 10.0.2.1 X-Rspamd-Queue-Id: 6991883939 X-Spamd-Bar: ++++++ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [6.60 / 15.00]; ARC_NA(0.00)[]; RCVD_COUNT_FIVE(0.00)[5]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; MV_CASE(0.50)[]; NEURAL_SPAM_SHORT(0.95)[0.953,0]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-usb@freebsd.org]; HAS_XAW(0.00)[]; AUTH_NA(1.00)[]; DMARC_NA(0.00)[dons.net.au]; NEURAL_SPAM_MEDIUM(1.00)[1.000,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; MX_GOOD(-0.01)[cached: midget.dons.net.au]; RCPT_COUNT_TWO(0.00)[2]; NEURAL_SPAM_LONG(1.00)[1.000,0]; R_SPF_NA(0.00)[]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:4739, ipnet:150.101.0.0/16, country:AU]; MID_RHS_MATCH_FROM(0.00)[]; IP_SCORE(2.26)[ip: (4.88), ipnet: 150.101.0.0/16(4.32), asn: 4739(2.10), country: AU(-0.01)]; RCVD_IN_DNSWL_LOW(-0.10)[131.137.101.150.list.dnswl.org : 127.0.5.1] X-Spam: Yes X-BeenThere: freebsd-usb@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: FreeBSD support for USB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 02 May 2019 08:31:15 -0000 > On 2 May 2019, at 06:15, Hans Petter Selasky wrote: > On 2019-05-01 10:34, O'Connor, Daniel wrote: >> I don't have a solid hypothesis for the failures as yes but one thing = I'd like to make sure is that the USB stack is keeping the USB hardware = busy with pending requests - does anyone know if the USB FIFO code does = that automatically? >=20 > Only the XHCI driver supports HW based double buffering of BULK = transfers. Ahh interesting - is that a ECHI hardware limitation or a driver one? > I suppose you are using BULK. Else you will need to use ISOCHRONOUS = transfers. Yes it's using bulk transfers. I did consider isochronous transfers when I started this project but I = wasn't sure if there would be enough bandwidth (but perhaps I read the = spec wrong). I imagine there would be enough for this data rate but we = have others at higher speeds (eg 35MB/sec). Related to bandwidth - are there any statistics gathered about how busy = a port is? Thanks -- Daniel O'Connor "The nice thing about standards is that there are so many of them to choose from." -- Andrew Tanenbaum