Messages in this thread | | | Date | Wed, 30 Mar 2022 22:24:35 +0800 | From | Brad Campbell <> | Subject | Re: Apple Thunderbolt Display chaining |
| |
On 30/3/22 21:43, Mika Westerberg wrote: > Hi, > > On Wed, Mar 30, 2022 at 09:19:52PM +0800, Brad Campbell wrote: >> Hey Mika, >> >> On 30/3/22 18:18, Mika Westerberg wrote: >>> Hi, >>> >>> On Tue, Mar 29, 2022 at 10:06:35PM +0800, Brad Campbell wrote: >>>>> Indeed, I did not add this to the "discovery" path yet. >>>>> >>>>> I wonder what happens if you change this: >>>>> >>>>> + tunnel = tb_tunnel_alloc_dp(tb, in, out, available_up, available_down, >>>>> + first ? 0 : 1); >>>>> >>>>> to this in your tree: >>>>> >>>>> + tunnel = tb_tunnel_alloc_dp(tb, in, out, available_up, available_down, >>>>> + first ? 1 : 0); >>>>> >>>> >>>> Here's where it gets all "Apple..y". On the iMac this does the job no matter which >>>> port the chain is plugged into. Boots and displays correctly first time, every time. >>>> >>>> It turns out on the laptop, one port works and the other doesn't. Changing the order >>>> simply changes which port works. So I assume the EFI sets up the first display using >>>> the first lane if it's in the first port, and the second if it's in the second. >>>> >>>> That means had I managed to perform the first test in the "other port" consistently, >>>> it would have worked there also. >>> >>> Can you try the below patch too? I hard-code the lane based on the >>> DP adapter number in TBT gen1. >>> >>> Let's first figure out proper solution to this issue and then look at >>> the other one. >>> >>> diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c >>> index a473cc7d9a8d..97d36a7bb527 100644 >>> --- a/drivers/thunderbolt/tunnel.c >>> +++ b/drivers/thunderbolt/tunnel.c >>> @@ -865,6 +865,7 @@ struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in, >> >> This one works from cold boot on both machines regardless of the port the chain is plugged into. >> It fails on both machines on any hotplug with the symptoms of allocating them both the same link. >> I added an extra debug into tunnel.c and verified that. > > Hm, okay. What if you change this: > > link_nr = in->port == 11 ? 1 : 0; > > to this > > link_nr = in->port == 11 ? 0 : 1; > > Please also keep the debugging you added too so we can see if it now > uses both lanes. >
Nope, that did the same thing. I wonder though. I'm testing it on the laptop and that reports : [ 0.442832] thunderbolt 0000:07:00.0: Thunderbolt 2 Switch: 8086:156d (Revision: 0, TB Version: 2)
Changing "if (in->sw->generation == 1)" to "if (in->sw->generation == 2)" on the laptop solves that.
I can't test hotplug properly on the iMac due to the radeon training issue.
The laptop still has the issue of a cold boot working in one socket and not the other, but hot plug is working correctly.
Regards, Brad
| |