Hello. On Mon, Feb 03, 2025 at 10:42:24AM GMT, Mika Westerberg wrote: > Hi, > > On Fri, Jan 31, 2025 at 01:41:27AM +0000, Mohammad Rahimi wrote: > > Updates the Connection Manager to disable the Gen 4 Link Recovery > > flow before transitioning from a Symmetric Link to an Asymmetric > > Link, as specified in recent changes to the USB4 v2 specification. > > > > According to the "USB4 2.0 ENGINEERING CHANGE NOTICE FORM" > > published in September 2024, the rationale for this change is: > > > > "Since the default value of the Target Asymmetric Link might be > > different than Symmetric Link and Gen 4 Link Recovery flow checks > > this field to make sure it matched the actual Negotiated Link Width, > > we’re removing the condition for a Disconnect in the Gen 4 Link > > Recovery flow when Target Asymmetric Link doesn’t match the actual > > Link width and adding a Connection Manager note to Disable Gen 4 Link > > Recovery flow before doing Asymmetric Transitions." > > > > Signed-off-by: Mohammad Rahimi <rahimi.mhmmd@xxxxxxxxx> > > I did some minor modifications and applied to thunderbolt.git/next. Please > let me know if I missed something. > Looks great. Just one question: In tb_configure_asym(), if tb_switch_set_link_width() fails, we won’t restore the link recovery status. Is that okay? > I tested on Intel reference hardware as well but on those link recovery is > already disabled so it pretty much does nothing. Below are the steps that I > followed: > > 1. Boot with "thunderbolt.asym_threshold=10000" so that the driver switches > links to asymmetric already upon first DP connect. > > 2. Connect USB4 v2 hub. > 3. Check link and PORT_CS_19: > > # tblist -v > Domain 0 Route 0: 8087:5781 Intel Barlow Host Router > Type: Router > UUID: c9680000... > Generation: USB4 > NVM version: 56.81 > > Domain 0 Route 1: 8087:1234 Intel Barlow HUB Router > Type: Router > Speed (Rx/Tx): 80/80 Gb/s > Authorized: No > UUID: e9688780... > Generation: USB4 > NVM version: 56.81 > > # tbdump -r 0 -a 1 -vv -N 1 PORT_CS_19 > 0x00d3 0x0004000e 0b00000000 00000100 00000000 00001110 .... PORT_CS_19 > [00:00] 0x0 Downstream Port Reset (DPR) > [01:01] 0x1 Request RS-FEC Gen 2 (RS2) > [02:02] 0x1 Request RS-FEC Gen 3 (RS3) > [03:03] 0x1 USB4 Port is Configured (PC) > [04:04] 0x0 USB4 Port is Inter-Domain (PID) > [16:16] 0x0 Enable Wake on Connect > [17:17] 0x0 Enable Wake on Disconnect > [18:18] 0x1 Enable Wake on USB4 Wake > [19:19] 0x0 Enable Wake on Inter-Domain > [24:24] 0x0 StartAsymmetricFlow > [30:30] 0x0 Initiate Gen 4 Link Recovery (ILR) > [31:31] 0x0 Enable Gen 4 Link Recovery (ELR) > > # tbdump -r 1 -a 1 -vv -N 1 PORT_CS_19 > 0x00d3 0x0004000e 0b00000000 00000100 00000000 00001110 .... PORT_CS_19 > [00:00] 0x0 Downstream Port Reset (DPR) > [01:01] 0x1 Request RS-FEC Gen 2 (RS2) > [02:02] 0x1 Request RS-FEC Gen 3 (RS3) > [03:03] 0x1 USB4 Port is Configured (PC) > [04:04] 0x0 USB4 Port is Inter-Domain (PID) > [16:16] 0x0 Enable Wake on Connect > [17:17] 0x0 Enable Wake on Disconnect > [18:18] 0x1 Enable Wake on USB4 Wake > [19:19] 0x0 Enable Wake on Inter-Domain > [24:24] 0x0 StartAsymmetricFlow > [30:30] 0x0 Initiate Gen 4 Link Recovery (ILR) > [31:31] 0x0 Enable Gen 4 Link Recovery (ELR) > > 3. Connect monitor to USB4 v2 hub. > 4. Check link and PORT_CS_19. > > # tblist -v > Domain 0 Route 0: 8087:5781 Intel Barlow Host Router > Type: Router > UUID: c9680000... > Generation: USB4 > NVM version: 56.81 > > Domain 0 Route 1: 8087:1234 Intel Barlow HUB Router > Type: Router > Speed (Rx/Tx): 120/40 Gb/s > Authorized: No > UUID: e9688780... > Generation: USB4 > NVM version: 56.81 > > # tbdump -r 0 -a 1 -vv -N 1 PORT_CS_19 > 0x00d3 0x0004000e 0b00000000 00000100 00000000 00001110 .... PORT_CS_19 > [00:00] 0x0 Downstream Port Reset (DPR) > [01:01] 0x1 Request RS-FEC Gen 2 (RS2) > [02:02] 0x1 Request RS-FEC Gen 3 (RS3) > [03:03] 0x1 USB4 Port is Configured (PC) > [04:04] 0x0 USB4 Port is Inter-Domain (PID) > [16:16] 0x0 Enable Wake on Connect > [17:17] 0x0 Enable Wake on Disconnect > [18:18] 0x1 Enable Wake on USB4 Wake > [19:19] 0x0 Enable Wake on Inter-Domain > [24:24] 0x0 StartAsymmetricFlow > [30:30] 0x0 Initiate Gen 4 Link Recovery (ILR) > [31:31] 0x0 Enable Gen 4 Link Recovery (ELR) > > # tbdump -r 1 -a 1 -vv -N 1 PORT_CS_19 > 0x00d3 0x0004000e 0b00000000 00000100 00000000 00001110 .... PORT_CS_19 > [00:00] 0x0 Downstream Port Reset (DPR) > [01:01] 0x1 Request RS-FEC Gen 2 (RS2) > [02:02] 0x1 Request RS-FEC Gen 3 (RS3) > [03:03] 0x1 USB4 Port is Configured (PC) > [04:04] 0x0 USB4 Port is Inter-Domain (PID) > [16:16] 0x0 Enable Wake on Connect > [17:17] 0x0 Enable Wake on Disconnect > [18:18] 0x1 Enable Wake on USB4 Wake > [19:19] 0x0 Enable Wake on Inter-Domain > [24:24] 0x0 StartAsymmetricFlow > [30:30] 0x0 Initiate Gen 4 Link Recovery (ILR) > [31:31] 0x0 Enable Gen 4 Link Recovery (ELR)
