Re: Linux Support for Thunderbolt using Apple Monitor

From: Francois Rigaut
Date: Wed May 09 2012 - 21:49:36 EST


Greg,

I went ahead and contacted John Ronciak at intel.
He gave a presentation on thunderbolt at the 2011 linux plumber conference.
Here is his answer:

"You are correct that most if not all issues related to Thunderbolt on Linux is due to BIOS problems. We have not seen anything other BIOS issues regarding Thunderbolt issues on Linux. When the BIOS is working correctly the hot-plug PCIe works fine wrt the kernel. These are things that cannot be fixed in the drivers or in kernel infrastructure. So newer systems are going to be better than older ones due to these BIOS issues."

Francois

On 10/05/12 02:05, Greg KH wrote:
On Sun, May 06, 2012 at 11:22:11AM +0800, Jiang Liu wrote:
I'm afraid it won't work by just changing the OSDW() return value.
After analysis the ACPI table, I guess the BIOS ACPI implementation doesn't
confirm to the ACPI specification for hotplug, it needs special support in
OS to enable Thunderbolt cable hotplug on that system. Maybe that's the
reason why it's only enabled on Apple's OSes, not sure it's due to technical
or business considerations.

This PCIe device "05:00.0 System peripheral: Intel Corporation Device 151a
(rev 01)" may play a role in the Thunderbolt cable hotplug operations, but
haven't figured it out yet.
Thanks for looking at this.

So either we need a BIOS update for this platform so that other
operating systems can work properly (i.e. full ACPI hotplug support), or
we write a new hotplug driver to handle this hardware properly.

Intel was rumored to have this working in their labs, I'll poke some
people to see if they have anything they can release...

thanks,

greg k-h
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