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| author | Mika Westerberg <mika.westerberg@linux.intel.com> | 2022-04-01 17:24:28 +0300 |
|---|---|---|
| committer | Mika Westerberg <mika.westerberg@linux.intel.com> | 2022-04-19 10:26:18 +0300 |
| commit | 9d2d0a5cf0ca063f417681cc33e767ce52615286 (patch) | |
| tree | a5f8c4deb919a2e471e8ba39290963f4717345cc /drivers/thunderbolt/tunnel.h | |
| parent | 259e0c71e552557294d4820c840f62185e135c3a (diff) | |
| download | lwn-9d2d0a5cf0ca063f417681cc33e767ce52615286.tar.gz lwn-9d2d0a5cf0ca063f417681cc33e767ce52615286.zip | |
thunderbolt: Use different lane for second DisplayPort tunnel
Brad reported that on Apple hardware with Light Ridge or Falcon Ridge
controller, plugging in a chain of Thunderbolt displays (Light Ridge
based controllers) causes all kinds of tearing and flickering. The
reason for this is that on Thunderbolt 1 hardware there is no lane
bonding so we have two independent 10 Gb/s lanes, and currently Linux
tunnels both displays through the lane 1. This makes the displays to
share the 10 Gb/s bandwidth which may not be enough for higher
resolutions.
For this reason make the second tunnel go through the lane 0 instead.
This seems to match what the macOS connection manager is also doing.
Reported-by: Brad Campbell <lists2009@fnarfbargle.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Tested-by: Brad Campbell <lists2009@fnarfbargle.com>
Diffstat (limited to 'drivers/thunderbolt/tunnel.h')
| -rw-r--r-- | drivers/thunderbolt/tunnel.h | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/thunderbolt/tunnel.h b/drivers/thunderbolt/tunnel.h index 03e56076b5bc..bb4d1f1d6d0b 100644 --- a/drivers/thunderbolt/tunnel.h +++ b/drivers/thunderbolt/tunnel.h @@ -71,8 +71,8 @@ struct tb_tunnel *tb_tunnel_alloc_pci(struct tb *tb, struct tb_port *up, struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in, bool alloc_hopid); struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in, - struct tb_port *out, int max_up, - int max_down); + struct tb_port *out, int link_nr, + int max_up, int max_down); struct tb_tunnel *tb_tunnel_alloc_dma(struct tb *tb, struct tb_port *nhi, struct tb_port *dst, int transmit_path, int transmit_ring, int receive_path, |