Re: Apple Thunderbolt Display chaining

From: Mika Westerberg
Date: Fri Apr 01 2022 - 10:39:41 EST

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In reply to: Brad Campbell: "Re: Apple Thunderbolt Display chaining"
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Hi,

On Fri, Apr 01, 2022 at 01:48:13PM +0800, Brad Campbell wrote:
> That I can do. I didn't crop or grep as I wasn't sure what might be additionally relevant.
> 2 machines, 2 ports, 4 cold boots. Each time just the Thnuderbolt displays chained.

Thanks for the logs! It looks like the Apple EFI CM always uses the lane
1 adapter.

Can you try the below patch? Fingers crossed that it solves the
chaining issue for both ;-) I had to patch the test.c because otherwise
unit tests fail to compile when enabled.

This should now setup the second tunnel always through the lane 0
adapter and thus share the bandwidth equally between the two lanes.

diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
index 8c20a50cc9d9..1ca6fe67ba56 100644
--- a/drivers/thunderbolt/tb.c
+++ b/drivers/thunderbolt/tb.c
@@ -1065,7 +1065,7 @@ static void tb_recalc_estimated_bandwidth(struct tb *tb)

static void tb_tunnel_dp(struct tb *tb)
{
- int available_up, available_down, ret;
+ int available_up, available_down, ret, link_nr;
struct tb_cm *tcm = tb_priv(tb);
struct tb_port *port, *in, *out;
struct tb_tunnel *tunnel;
@@ -1110,6 +1110,20 @@ static void tb_tunnel_dp(struct tb *tb)
return;
}

+ /*
+ * This is only applicable to links that are not bonded (so
+ * when Thunderbolt 1 hardware is involved somewhere in the
+ * topology). For these try to share the DP bandwidth between
+ * the two lanes.
+ */
+ link_nr = 1;
+ list_for_each_entry(tunnel, &tcm->tunnel_list, list) {
+ if (tb_tunnel_is_dp(tunnel)) {
+ link_nr = 0;
+ break;
+ }
+ }
+
/*
* DP stream needs the domain to be active so runtime resume
* both ends of the tunnel.
@@ -1142,7 +1156,8 @@ static void tb_tunnel_dp(struct tb *tb)

tb_attach_bandwidth_group(tcm, in, out);

- tunnel = tb_tunnel_alloc_dp(tb, in, out, available_up, available_down);
+ tunnel = tb_tunnel_alloc_dp(tb, in, out, link_nr, available_up,
+ available_down);
if (!tunnel) {
tb_port_dbg(out, "could not allocate DP tunnel\n");
goto err_detach_group;
diff --git a/drivers/thunderbolt/test.c b/drivers/thunderbolt/test.c
index 6f027b3c2efe..5884c616b047 100644
--- a/drivers/thunderbolt/test.c
+++ b/drivers/thunderbolt/test.c
@@ -1365,7 +1365,7 @@ static void tb_test_tunnel_dp(struct kunit *test)
in = &host->ports[5];
out = &dev->ports[13];

- tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel != NULL);
KUNIT_EXPECT_EQ(test, tunnel->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel->src_port, in);
@@ -1411,7 +1411,7 @@ static void tb_test_tunnel_dp_chain(struct kunit *test)
in = &host->ports[5];
out = &dev4->ports[14];

- tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel != NULL);
KUNIT_EXPECT_EQ(test, tunnel->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel->src_port, in);
@@ -1461,7 +1461,7 @@ static void tb_test_tunnel_dp_tree(struct kunit *test)
in = &dev2->ports[13];
out = &dev5->ports[13];

- tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel != NULL);
KUNIT_EXPECT_EQ(test, tunnel->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel->src_port, in);
@@ -1526,7 +1526,7 @@ static void tb_test_tunnel_dp_max_length(struct kunit *test)
in = &dev6->ports[13];
out = &dev12->ports[13];

- tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel != NULL);
KUNIT_EXPECT_EQ(test, tunnel->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel->src_port, in);
@@ -1604,7 +1604,7 @@ static void tb_test_tunnel_3dp(struct kunit *test)
KUNIT_ASSERT_EQ(test, tunnel1->npaths, 3);
KUNIT_ASSERT_EQ(test, tunnel1->paths[0]->path_length, 3);

- tunnel2 = tb_tunnel_alloc_dp(NULL, in2, out2, 0, 0);
+ tunnel2 = tb_tunnel_alloc_dp(NULL, in2, out2, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel2 != NULL);
KUNIT_EXPECT_EQ(test, tunnel2->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel2->src_port, in2);
@@ -1612,7 +1612,7 @@ static void tb_test_tunnel_3dp(struct kunit *test)
KUNIT_ASSERT_EQ(test, tunnel2->npaths, 3);
KUNIT_ASSERT_EQ(test, tunnel2->paths[0]->path_length, 4);

- tunnel3 = tb_tunnel_alloc_dp(NULL, in3, out3, 0, 0);
+ tunnel3 = tb_tunnel_alloc_dp(NULL, in3, out3, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel3 != NULL);
KUNIT_EXPECT_EQ(test, tunnel3->type, TB_TUNNEL_DP);
KUNIT_EXPECT_PTR_EQ(test, tunnel3->src_port, in3);
@@ -1709,7 +1709,7 @@ static void tb_test_tunnel_port_on_path(struct kunit *test)
in = &dev2->ports[13];
out = &dev5->ports[13];

- dp_tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ dp_tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, dp_tunnel != NULL);

KUNIT_EXPECT_TRUE(test, tb_tunnel_port_on_path(dp_tunnel, in));
@@ -2091,7 +2091,7 @@ static void tb_test_credit_alloc_dp(struct kunit *test)
in = &host->ports[5];
out = &dev->ports[14];

- tunnel = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ tunnel = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, tunnel != NULL);
KUNIT_ASSERT_EQ(test, tunnel->npaths, (size_t)3);

@@ -2327,7 +2327,7 @@ static struct tb_tunnel *TB_TEST_DP_TUNNEL1(struct kunit *test,

in = &host->ports[5];
out = &dev->ports[13];
- dp_tunnel1 = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ dp_tunnel1 = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, dp_tunnel1 != NULL);
KUNIT_ASSERT_EQ(test, dp_tunnel1->npaths, (size_t)3);

@@ -2364,7 +2364,7 @@ static struct tb_tunnel *TB_TEST_DP_TUNNEL2(struct kunit *test,

in = &host->ports[6];
out = &dev->ports[14];
- dp_tunnel2 = tb_tunnel_alloc_dp(NULL, in, out, 0, 0);
+ dp_tunnel2 = tb_tunnel_alloc_dp(NULL, in, out, 1, 0, 0);
KUNIT_ASSERT_TRUE(test, dp_tunnel2 != NULL);
KUNIT_ASSERT_EQ(test, dp_tunnel2->npaths, (size_t)3);

diff --git a/drivers/thunderbolt/tunnel.c b/drivers/thunderbolt/tunnel.c
index d08441f36e7a..08fddd469ab6 100644
--- a/drivers/thunderbolt/tunnel.c
+++ b/drivers/thunderbolt/tunnel.c
@@ -1086,6 +1086,7 @@ struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in,
* @tb: Pointer to the domain structure
* @in: DP in adapter port
* @out: DP out adapter port
+ * @link_nr: Preferred lane adapter when the link is not bonded
* @max_up: Maximum available upstream bandwidth for the DP tunnel (%0
* if not limited)
* @max_down: Maximum available downstream bandwidth for the DP tunnel
@@ -1097,8 +1098,8 @@ struct tb_tunnel *tb_tunnel_discover_dp(struct tb *tb, struct tb_port *in,
* Return: Returns a tb_tunnel on success or NULL on failure.
*/
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 *tunnel;
struct tb_path **paths;
@@ -1124,21 +1125,21 @@ struct tb_tunnel *tb_tunnel_alloc_dp(struct tb *tb, struct tb_port *in,
paths = tunnel->paths;

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);
diff --git a/drivers/thunderbolt/tunnel.h b/drivers/thunderbolt/tunnel.h
index ea605046d41f..89d6328dd04f 100644
--- a/drivers/thunderbolt/tunnel.h
+++ b/drivers/thunderbolt/tunnel.h
@@ -77,8 +77,8 @@ 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,
--
2.32.0

Next message: Sasha Levin: "[PATCH AUTOSEL 5.17 132/149] net/mlx5e: Remove overzealous validations in netlink EEPROM query"
Previous message: Sasha Levin: "[PATCH AUTOSEL 5.17 130/149] net: account alternate interface name memory"
In reply to: Brad Campbell: "Re: Apple Thunderbolt Display chaining"
Next in thread: Brad Campbell: "Re: Apple Thunderbolt Display chaining"
Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]