Messages in this thread Patch in this message | | | Date | Wed, 30 Mar 2022 13:18:59 +0300 | From | Mika Westerberg <> | Subject | Re: Apple Thunderbolt Display chaining |
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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, struct tb_tunnel *tunnel; struct tb_path **paths; struct tb_path *path; + int link_nr; if (WARN_ON(!in->cap_adap || !out->cap_adap)) return NULL; @@ -883,22 +884,32 @@ struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in, paths = tunnel->paths; + /* + * Hard code the lane for both DP IN adapters in first + * generation hardware. This should follow what the Apple boot + * firmware does. + */ + if (in->sw->generation == 1) + link_nr = in->port == 11 ? 1 : 0; + else + link_nr = 0; + path = tb_path_alloc(tb, in, TB_DP_VIDEO_HOPID, out, TB_DP_VIDEO_HOPID, - 1, "Video"); + link_nr, "Video"); if (!path) goto err_free; tb_dp_init_video_path(path); paths[TB_DP_VIDEO_PATH_OUT] = path; path = tb_path_alloc(tb, in, TB_DP_AUX_TX_HOPID, out, - TB_DP_AUX_TX_HOPID, 1, "AUX TX"); + TB_DP_AUX_TX_HOPID, link_nr, "AUX TX"); if (!path) goto err_free; tb_dp_init_aux_path(path); paths[TB_DP_AUX_PATH_OUT] = path; path = tb_path_alloc(tb, out, TB_DP_AUX_RX_HOPID, in, - TB_DP_AUX_RX_HOPID, 1, "AUX RX"); + TB_DP_AUX_RX_HOPID, link_nr, "AUX RX"); if (!path) goto err_free; tb_dp_init_aux_path(path);
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