[elrepo] CentOS/Kernel 3.18/Thunderbolt2

[Israel Brewster]

On Jan 26, 2015, at 11:58 AM, Alan Bartlett <ajb at elrepo.org> wrote:

> On 26 January 2015 at 19:24, Alan Bartlett <ajb at elrepo.org> wrote:
>> On 26 January 2015 at 19:14, Israel Brewster <israel at ravnalaska.net> wrote:
>>> 
>>> Awesome, thanks! I'll keep an eye out. Are the releases announced here/elsewhere, or should I just check yum update periodically? Thanks again!
>> 
>> Yes, all releases are announced on this m/l.
>> 
>> For reference (and so you know for what to look out), the
>> announcements of the last three package sets built are here [1][2][3]
>> in the m/l archive.
>> 
>> Alan.
>> 
>> [1] http://lists.elrepo.org/pipermail/elrepo/2015-January/002505.html
>> [2] http://lists.elrepo.org/pipermail/elrepo/2015-January/002506.html
>> [3] http://lists.elrepo.org/pipermail/elrepo/2015-January/002507.html
> 
> Hmm . . . I've taken a look at the Kconfig file and the section
> relevant to the kernel configuration that references "Thunderbolt"
> reads as follows --
> 
> [quote]
> menuconfig THUNDERBOLT
>    tristate "Thunderbolt support for Apple devices"
>    depends on PCI
>    select CRC32
>    help
>      Cactus Ridge Thunderbolt Controller driver
>      This driver is required if you want to hotplug Thunderbolt devices on
>      Apple hardware.
> 
>      Device chaining is currently not supported.
> 
>      To compile this driver a module, choose M here. The module will be
>      called thunderbolt.
> [/quote]
> 
> The references to "Apple devices" and "Apple hardware" makes me think
> that is not the correct configuration choice.
> 
> I can certainly "turn it on", as a module but I have my doubts as to
> whether it will help.

It looks like you might be right, but perhaps not for the reasons you were thinking. The key phrase in this information, to my mind, is: "Cactus Ridge Thunderbolt Controller driver". Cactus Ridge is the code name for Intel's Thunderbolt controllers that accompanied Ivy Bridge systems (http://ark.intel.com/products/codename/57097/Cactus-Ridge). It's *possible* that that specific chip was only used in Apple hardware (certainly Apple hardware is the primary user of thunderbolt controllers), but I don't know of any reason why that would be the case *necessarily*.

That said, the chip in my system (and, in fact, any thunderbolt 2 system I am aware of at the moment) is a "Falcon Ridge" controller, released Q3 2013 according to the Wikipedia article. As such, I also have my doubts that the "Cactus Ridge" controller driver will help. It's possible the Linux kernel simply doesn't support thunderbolt 2 (yet?).

On the other hand, there is this: http://permalink.gmane.org/gmane.linux.kernel/1717419 which seems to indicate a patch to make things work with the Falcon Ridge controller was available back in June of last year. I think. It also references Apple hardware, but the controller is the same. And this: http://www.gossamer-threads.com/lists/linux/kernel/1935522 which seems to indicate that simply adding some ID's to the Cactus Ridge driver makes it work with thunderbolt2 (Falcon Ridge) controllers - so perhaps the help simply hasn't been updated?

I suppose, however, that it is also possible that if I want to use the thunderbolt card, I'll have to run windows. Which would stink. Maybe there is a Linux kernel mailing list I should be asking on?

-----------------------------------------------
Israel Brewster
Systems Analyst II
Ravn Alaska
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7293
-----------------------------------------------


> 
> Alan.
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