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From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org,
	Andreas Noever <andreas.noever@gmail.com>,
	Michael Jamet <michael.jamet@intel.com>,
	Yehezkel Bernat <YehezkelShB@gmail.com>,
	Rajmohan Mani <rajmohan.mani@intel.com>,
	Nicholas Johnson <nicholas.johnson-opensource@outlook.com.au>,
	Lukas Wunner <lukas@wunner.de>,
	Alan Stern <stern@rowland.harvard.edu>,
	Mario.Limonciello@dell.com,
	Anthony Wong <anthony.wong@canonical.com>,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 06/22] thunderbolt: Add support for lane bonding
Date: Tue, 1 Oct 2019 15:53:20 +0300
Message-ID: <20191001125320.GN2714@lahna.fi.intel.com> (raw)
In-Reply-To: <20191001123808.GA2954373@kroah.com>

On Tue, Oct 01, 2019 at 02:38:08PM +0200, Greg Kroah-Hartman wrote:
> On Tue, Oct 01, 2019 at 02:38:14PM +0300, Mika Westerberg wrote:
> > Lane bonding allows aggregating the two 10/20 Gb/s (depending on the
> > generation) lanes into a single 20/40 Gb/s bonded link. This allows
> > sharing the full bandwidth more efficiently. In order to establish lane
> > bonding we need to check that the lane bonding is possible through LC
> > and that both end of the link actually supports 2x widths. This also
> > means that all the paths should be established through the primary port
> > so update tb_path_alloc() to handle this as well.
> > 
> > Lane bonding is supported starting from Falcon Ridge (2nd generation)
> > controllers.
> 
> Are we only going to be allowed to "bond" two links together?  Or will
> we be doing more than 2 in the future?  If more, then we might want to
> think of a different way to specify these...

AFAICT only two lanes are available in USB4. This goes over USB type-C
using the two lanes there.

Of course I don't know if in future there will be USB4 1.1 or something
that adds more lanes so if you think there is a better way to specify
these, I'm happy to implement that instead :) 

> Anyway, one tiny nit below:
> 
> > 
> > Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
> > ---
> >  .../ABI/testing/sysfs-bus-thunderbolt         |  17 ++
> >  drivers/thunderbolt/icm.c                     |  18 +-
> >  drivers/thunderbolt/lc.c                      |  28 ++
> >  drivers/thunderbolt/path.c                    |  30 +-
> >  drivers/thunderbolt/switch.c                  | 274 ++++++++++++++++++
> >  drivers/thunderbolt/tb.c                      |  21 ++
> >  drivers/thunderbolt/tb.h                      |  10 +
> >  drivers/thunderbolt/tb_msgs.h                 |   2 +
> >  drivers/thunderbolt/tb_regs.h                 |  20 ++
> >  drivers/thunderbolt/tunnel.c                  |  19 +-
> >  10 files changed, 429 insertions(+), 10 deletions(-)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-thunderbolt b/Documentation/ABI/testing/sysfs-bus-thunderbolt
> > index b21fba14689b..2c9166f6fa97 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-thunderbolt
> > +++ b/Documentation/ABI/testing/sysfs-bus-thunderbolt
> > @@ -104,6 +104,23 @@ Contact:	thunderbolt-software@lists.01.org
> >  Description:	This attribute contains name of this device extracted from
> >  		the device DROM.
> >  
> > +What:		/sys/bus/thunderbolt/devices/.../link_speed
> > +Date:		Apr 2020
> > +KernelVersion:	5.6
> > +Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
> > +Description:	This attribute reports the current upstream link speed
> > +		in Gb/s per lane. If there are two lanes they both are
> > +		running at the same speed. Use link_width to determine
> > +		whether the two lanes are bonded or not.
> > +
> > +What:		/sys/bus/thunderbolt/devices/.../link_width
> > +Date:		Apr 2020
> > +KernelVersion:	5.6
> > +Contact:	Mika Westerberg <mika.westerberg@linux.intel.com>
> > +Description:	This attribute reports the current upstream link width.
> > +		It is 1 for single lane link (or two single lane links)
> > +		and 2 for bonded dual lane link.
> > +
> >  What:		/sys/bus/thunderbolt/devices/.../vendor
> >  Date:		Sep 2017
> >  KernelVersion:	4.13
> > diff --git a/drivers/thunderbolt/icm.c b/drivers/thunderbolt/icm.c
> > index 6550f68f92ce..9c9c6ea2b790 100644
> > --- a/drivers/thunderbolt/icm.c
> > +++ b/drivers/thunderbolt/icm.c
> > @@ -567,7 +567,8 @@ static struct tb_switch *add_switch(struct tb_switch *parent_sw, u64 route,
> >  				    size_t ep_name_size, u8 connection_id,
> >  				    u8 connection_key, u8 link, u8 depth,
> >  				    enum tb_security_level security_level,
> > -				    bool authorized, bool boot)
> > +				    bool authorized, bool boot, bool dual_lane,
> > +				    bool speed_gen3)
> 
> That's just a crazy amount of function parameters, with no way of
> remembering what is what, especially when you add 2 more booleans at the
> end.
> 
> It's your code, but ugh, that's going to be hard to maintain over time
> :(

Good point. I'll see if I can simplify it in the next version.

  reply index

Thread overview: 95+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-01 11:38 [RFC PATCH 00/22] thunderbolt: Add support for USB4 Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 01/22] thunderbolt: Introduce tb_switch_is_icm() Mika Westerberg
2019-10-01 12:10   ` Greg Kroah-Hartman
2019-10-01 12:46     ` Mika Westerberg
2019-10-01 13:36       ` Mario.Limonciello
2019-10-01 13:48         ` Mika Westerberg
2019-10-01 13:50           ` Mario.Limonciello
2019-10-01 13:52             ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 02/22] thunderbolt: Log switch route string on config read/write timeout Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 03/22] thunderbolt: Log warning if adding switch fails Mika Westerberg
2019-10-01 12:18   ` Greg Kroah-Hartman
2019-10-01 12:48     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 04/22] thunderbolt: Make tb_sw_write() take const parameter Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 05/22] thunderbolt: Add helper macros to iterate over switch ports Mika Westerberg
2019-10-02 14:17   ` Oliver Neukum
2019-10-02 14:28     ` Mika Westerberg
2019-10-06 12:15       ` Lukas Wunner
2019-10-01 11:38 ` [RFC PATCH 06/22] thunderbolt: Add support for lane bonding Mika Westerberg
2019-10-01 12:38   ` Greg Kroah-Hartman
2019-10-01 12:53     ` Mika Westerberg [this message]
2019-10-02 14:21       ` Oliver Neukum
2019-10-02 14:30         ` Mika Westerberg
2019-10-03  8:25           ` Oliver Neukum
2019-10-03  8:53             ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 07/22] thunderbolt: Add default linking between ports if not provided by DROM Mika Westerberg
2019-10-01 12:39   ` Greg Kroah-Hartman
2019-10-01 13:14     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 08/22] thunderbolt: Add downstream PCIe port mappings for Alpine and Titan Ridge Mika Westerberg
2019-10-01 12:40   ` Greg Kroah-Hartman
2019-10-01 13:27     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 09/22] thunderbolt: Convert basic adapter register names to follow the USB4 spec Mika Westerberg
2019-10-01 12:41   ` Greg Kroah-Hartman
2019-10-01 13:28     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 10/22] thunderbolt: Convert PCIe adapter register names to use USB4 names Mika Westerberg
2019-10-01 12:42   ` Greg Kroah-Hartman
2019-10-01 11:38 ` [RFC PATCH 11/22] thunderbolt: Convert DP adapter register names to follow the USB4 spec Mika Westerberg
2019-10-01 12:42   ` Greg Kroah-Hartman
2019-10-01 11:38 ` [RFC PATCH 12/22] thunderbolt: Add Display Port CM handshake for Titan Ridge devices Mika Westerberg
2019-10-01 12:44   ` Greg Kroah-Hartman
2019-10-01 13:30     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 13/22] thunderbolt: Add Display Port adapter pairing and resource management Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 14/22] thunderbolt: Add bandwidth management for Display Port tunnels Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 15/22] thunderbolt: Make tb_find_port() available to other files Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 16/22] thunderbolt: Call tb_eeprom_get_drom_offset() from tb_eeprom_read_n() Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 17/22] thunderbolt: Add initial support for USB4 Mika Westerberg
2019-10-01 12:47   ` Greg Kroah-Hartman
2019-10-01 13:09     ` Mika Westerberg
2019-10-01 14:53       ` Greg Kroah-Hartman
2019-10-01 14:59         ` Mario.Limonciello
2019-10-01 15:13           ` Mika Westerberg
2019-10-01 15:22           ` Greg KH
2019-10-01 15:32             ` Mika Westerberg
2019-10-01 15:07         ` Mika Westerberg
2019-10-01 15:19           ` Greg Kroah-Hartman
2019-10-01 15:26             ` Mika Westerberg
2019-10-01 16:27           ` Oliver Neukum
2019-10-02  8:30             ` Mika Westerberg
2019-10-02  8:39               ` Greg Kroah-Hartman
2019-10-02  8:49                 ` Mika Westerberg
2019-10-01 17:05   ` Mario.Limonciello
2019-10-01 18:14     ` Mario.Limonciello
2019-10-02  8:39       ` Mika Westerberg
2019-10-02 15:09         ` Mario.Limonciello
2019-10-02 15:36           ` Yehezkel Bernat
2019-10-02 16:00             ` Mario.Limonciello
2019-10-03  8:00               ` Mika Westerberg
2019-10-03 14:41                 ` Mario.Limonciello
2019-10-04  7:54                   ` Mika Westerberg
2019-10-04  8:07                     ` Yehezkel Bernat
2019-10-04  8:19                       ` Mika Westerberg
2019-10-04 11:19                         ` Yehezkel Bernat
2019-10-04 14:05                           ` Mario.Limonciello
2019-10-04 14:19                             ` Mario.Limonciello
2019-10-04 14:21                             ` Mika Westerberg
     [not found]                               ` <1570201357.2.0@kellner.me>
2019-10-04 15:16                                 ` Mika Westerberg
2019-10-04 15:22                                   ` Christian Kellner
2019-10-02  8:34     ` Mika Westerberg
2019-10-02 15:04       ` Mario.Limonciello
2019-10-01 11:38 ` [RFC PATCH 18/22] thunderbolt: Make tb_switch_find_cap() available to other files Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 19/22] thunderbolt: Add support for Time Management Unit Mika Westerberg
2019-10-02 16:52   ` Mani, Rajmohan
2019-10-03  8:01     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 20/22] thunderbolt: Add support for USB tunnels Mika Westerberg
2019-10-03  8:42   ` Oliver Neukum
2019-10-03  8:52     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 21/22] thunderbolt: Update documentation with the USB4 information Mika Westerberg
2019-10-01 14:17   ` Mario.Limonciello
2019-10-01 14:21     ` Mika Westerberg
2019-10-01 11:38 ` [RFC PATCH 22/22] thunderbolt: Do not start firmware unless asked by the user Mika Westerberg
2019-10-01 14:43   ` Mario.Limonciello
2019-10-01 14:58     ` Mika Westerberg
2019-10-01 16:53       ` Mario.Limonciello
2019-10-02  8:48         ` Mika Westerberg
2019-10-01 12:49 ` [RFC PATCH 00/22] thunderbolt: Add support for USB4 Greg Kroah-Hartman
2019-10-01 13:42   ` Mika Westerberg

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