From: Mika Westerberg <mika.westerberg@linux.intel.com>
To: Lukas Wunner <lukas@wunner.de>
Cc: Andreas Noever <andreas.noever@gmail.com>,
Michael Jamet <michael.jamet@intel.com>,
Yehezkel Bernat <YehezkelShB@gmail.com>,
Stephen Hemminger <stephen@networkplumber.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 4/5] thunderbolt: Correlate PCI devices with Thunderbolt ports
Date: Mon, 10 Sep 2018 12:44:54 +0300 [thread overview]
Message-ID: <20180910094454.GJ14465@lahna.fi.intel.com> (raw)
In-Reply-To: <f53ea40a7487e145aa1a62c347cef1814072e140.1536517047.git.lukas@wunner.de>
Hi Lukas,
On Sun, Sep 09, 2018 at 11:42:01PM +0200, Lukas Wunner wrote:
> Ideas what we can do with correlation:
>
> * Represent the relationship between PCI devices and Thunderbolt ports
> with symlinks in sysfs.
I wonder is that really useful? I don't think we should be adding sysfs
entries without any real reason why it would be needed and who would be
using them.
> * Thunderbolt controllers up to revision 1 of Cactus Ridge 4C have to
> use INTx because MSI signaling is broken. This results in hotplug
> ports sharing interrupts with other devices and, when daisy-chaining
> multiple affected Thunderbolt controllers, can lead to extremely
> unbalanced interrupt usage. To avoid this we could prefer downstream
> ports for tunnel establishment which do not share interrupts (based
> on the nr_actions field of the correlated PCI device's irq_desc).
>
> * Alternatively, we could use non-working MSI signaling on affected
> controllers and synthesize an interrupt whenever a tunnel is
> established or goes down on unplug.
Problem I see with this patch as it stands is that you add 200+ lines of
code into the driver that is not being used by anything as far as I
understand it.
next prev parent reply other threads:[~2018-09-10 9:45 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-09 21:42 [PATCH 0/5] Thunderbolt material for v4.20 Lukas Wunner
2018-09-09 21:42 ` [PATCH 4/5] thunderbolt: Correlate PCI devices with Thunderbolt ports Lukas Wunner
2018-09-10 9:44 ` Mika Westerberg [this message]
2018-09-13 9:43 ` Yehezkel Bernat
2018-09-13 9:57 ` Mika Westerberg
2018-09-09 21:42 ` [PATCH 5/5] MAINTAINERS: Add Lukas Wunner as co-maintainer of thunderbolt Lukas Wunner
2018-09-10 9:33 ` Mika Westerberg
2018-09-10 10:25 ` Lukas Wunner
2018-09-10 12:13 ` Mika Westerberg
2018-09-13 8:58 ` Mika Westerberg
2018-09-13 9:43 ` Greg Kroah-Hartman
2018-09-17 22:34 ` Andreas Noever
2018-09-19 10:16 ` Mika Westerberg
2018-09-09 21:42 ` [PATCH 3/5] thunderbolt: Move upstream_port to struct tb Lukas Wunner
2018-09-09 21:42 ` [PATCH 2/5] thunderbolt: Obtain PCI slot number from DROM Lukas Wunner
2018-09-10 9:52 ` Mika Westerberg
2018-09-09 21:42 ` [PATCH 1/5] thunderbolt: Skip disabled ports on tunnel establishment Lukas Wunner
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