Messages in this thread | | | Date | Mon, 4 Apr 2022 15:53:03 +0300 | From | Mika Westerberg <> | Subject | Re: Apple Thunderbolt Display chaining |
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Hi,
On Mon, Apr 04, 2022 at 07:38:06PM +0800, Brad Campbell wrote: > > Hm, you mean you don't see the timeout errors and stuff with the first > > patch applied? > > I see the config timeout errors and the controller locking up after a > couple of unplugs, but when it does configure the DP channels, they > both come up every time. > > So, with the original patch when thunderbolt discovery works, displays > both work. With the latest patch, whether or not the hotplug works, > the radeon driver fails to bring up the parent head. > > Both suffer from the controller config timeout reads on unplug causing > it to become unresponsive after a couple of re-plug cycles (3 if I'm > lucky).
I suspect the same issue is even with the first patch but it just manifests differently. I think the timeouts are the key here and we need to figure out why they happen.
> > I think I will make this current one a proper patch and submit upstream > > later this week (will CC you too). For the iMac issue we may need to > > debug it further. Not sure if you answered this one already but on iMac > > on macOS does it work always when you plug in the whole chain? > > > Yes, MacOS works fine in any order on any port. > > There is a difference in the way something is set up between what the > EFI does and what Linux does.
Agree.
> If I wait for the Chime, then a bit longer and plug the chain in > (before the bootloader starts), Linux sets up both heads and hotplug / > replug works. > > If I cold boot with the chain plugged in, the EFI sets up one head and > Linux configures the other. Replug fails with the clock-recovery error > in that case. > > The difference seems to be when EFI sets up, on re-plug it sets up the > child display first (303 vs 3) and that causes the issue. Repeated > tests can get difficult as often on the second or third plug (or > unplug) the controller locks up and no longer responds to events. > > I'll try and get a couple of clear dmesg with your last debug patch > because it appear the chain is being discovered in a different order > depending on whether or not the EFI set it up.
That would be helpful.
> I received my brand new Titan Ridge board today (Gigabyte B550 > Vision-d-p) and with a modified Thunderbolt rom and the last patch it > detects and runs both Thunderbolt displays from a cold boot. Hotplug > fails, and there are other issues related to warm boot, but they'll > all have to wait until I get a serial console up.
Hehe, OK.
> Appreciate the persistence with this.
My pleasure ;-)
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