Hi Mika, On Mon, Nov 09, 2026 at 12:18:52PM +0100, Mika Westerberg wrote: > Please use tbdump from tbtools [1]. It knows the registers. Something like > this: > > https://github.com/intel/tbtools/wiki/Useful-Commands#dump-lane-adapter-capability-for-current-link-capabilities-and-status Thanks, here it is (tbtools 0.8.0). Domain 1 route 0 is the AMD host router, route 2 is the DEG2 (JHL9480). Both lane adapters on each side are included, followed by tbadapters for reference. tbtools 0.8.0, kernel 7.2.15, BIOS 1.06, 2026-11-09 11:23 UTC # tblist -A Domain 0 Domain 0 Route 0: 0000:0000 Domain 1 Domain 1 Route 0: 0000:0000 Domain 1 Route 0 Adapter 2 Index 1: 7fea:1032 Domain 1 Route 2: 041f:d002 Micro Computer (HK) Tech. Ltd. TBGAA # tbdump -d 1 -r 0 -a 2 -N 2 -vv LANE_ADP_CS_0 0x0080 0x003c01c0 0b00000000 00111100 00000001 11000000 .<.. LANE_ADP_CS_0 [00:07] 0xc0 Next Capability Pointer [08:15] 0x1 Capability ID [16:19] 0xc Supported Link Speeds [20:21] 0x3 Supported Link Widths (SLW) [22:23] 0x0 Gen 4 Asymmetric Support (G4AS) [26:26] 0x0 CL0s Support [27:27] 0x0 CL1 Support [28:28] 0x0 CL2 Support 0x0081 0x4828003c 0b01001000 00101000 00000000 00111100 H(.< LANE_ADP_CS_1 [00:03] 0xc Target Link Speed → Router shall attempt Gen 3 speed [04:05] 0x3 Target Link Width → Establish a Symmetric Link [06:07] 0x0 Target Asymmetric Link → Establish Symmetric Link [10:10] 0x0 CL0s Enable [11:11] 0x0 CL1 Enable [12:12] 0x0 CL2 Enable [14:14] 0x0 Lane Disable (LD) [15:15] 0x0 Lane Bonding (LB) [16:19] 0x8 Current Link Speed → Gen 2 [20:25] 0x2 Negotiated Link Width → Symmetric Link (x2) [26:29] 0x2 Adapter State → CL0 [30:30] 0x1 PM Secondary (PMS) # tbdump -d 1 -r 0 -a 3 -N 2 -vv LANE_ADP_CS_0 0x0080 0x003c0100 0b00000000 00111100 00000001 00000000 .<.. LANE_ADP_CS_0 [00:07] 0x0 Next Capability Pointer [08:15] 0x1 Capability ID [16:19] 0xc Supported Link Speeds [20:21] 0x3 Supported Link Widths (SLW) [22:23] 0x0 Gen 4 Asymmetric Support (G4AS) [26:26] 0x0 CL0s Support [27:27] 0x0 CL1 Support [28:28] 0x0 CL2 Support 0x0081 0x4828003c 0b01001000 00101000 00000000 00111100 H(.< LANE_ADP_CS_1 [00:03] 0xc Target Link Speed → Router shall attempt Gen 3 speed [04:05] 0x3 Target Link Width → Establish a Symmetric Link [06:07] 0x0 Target Asymmetric Link → Establish Symmetric Link [10:10] 0x0 CL0s Enable [11:11] 0x0 CL1 Enable [12:12] 0x0 CL2 Enable [14:14] 0x0 Lane Disable (LD) [15:15] 0x0 Lane Bonding (LB) [16:19] 0x8 Current Link Speed → Gen 2 [20:25] 0x2 Negotiated Link Width → Symmetric Link (x2) [26:29] 0x2 Adapter State → CL0 [30:30] 0x1 PM Secondary (PMS) # tbdump -d 1 -r 2 -a 1 -N 2 -vv LANE_ADP_CS_0 0x0036 0x0cfe01c0 0b00001100 11111110 00000001 11000000 .... LANE_ADP_CS_0 [00:07] 0xc0 Next Capability Pointer [08:15] 0x1 Capability ID [16:19] 0xe Supported Link Speeds [20:21] 0x3 Supported Link Widths (SLW) [22:23] 0x3 Gen 4 Asymmetric Support (G4AS) [26:26] 0x1 CL0s Support [27:27] 0x1 CL1 Support [28:28] 0x0 CL2 Support 0x0037 0x4828003e 0b01001000 00101000 00000000 00111110 H(.> LANE_ADP_CS_1 [00:03] 0xe Target Link Speed → Router shall attempt Gen 4 speed [04:05] 0x3 Target Link Width → Establish a Symmetric Link [06:07] 0x0 Target Asymmetric Link → Establish Symmetric Link [10:10] 0x0 CL0s Enable [11:11] 0x0 CL1 Enable [12:12] 0x0 CL2 Enable [14:14] 0x0 Lane Disable (LD) [15:15] 0x0 Lane Bonding (LB) [16:19] 0x8 Current Link Speed → Gen 2 [20:25] 0x2 Negotiated Link Width → Symmetric Link (x2) [26:29] 0x2 Adapter State → CL0 [30:30] 0x1 PM Secondary (PMS) # tbdump -d 1 -r 2 -a 2 -N 2 -vv LANE_ADP_CS_0 0x0036 0x0cfe0100 0b00001100 11111110 00000001 00000000 .... LANE_ADP_CS_0 [00:07] 0x0 Next Capability Pointer [08:15] 0x1 Capability ID [16:19] 0xe Supported Link Speeds [20:21] 0x3 Supported Link Widths (SLW) [22:23] 0x3 Gen 4 Asymmetric Support (G4AS) [26:26] 0x1 CL0s Support [27:27] 0x1 CL1 Support [28:28] 0x0 CL2 Support 0x0037 0x4828003e 0b01001000 00101000 00000000 00111110 H(.> LANE_ADP_CS_1 [00:03] 0xe Target Link Speed → Router shall attempt Gen 4 speed [04:05] 0x3 Target Link Width → Establish a Symmetric Link [06:07] 0x0 Target Asymmetric Link → Establish Symmetric Link [10:10] 0x0 CL0s Enable [11:11] 0x0 CL1 Enable [12:12] 0x0 CL2 Enable [14:14] 0x0 Lane Disable (LD) [15:15] 0x0 Lane Bonding (LB) [16:19] 0x8 Current Link Speed → Gen 2 [20:25] 0x2 Negotiated Link Width → Symmetric Link (x2) [26:29] 0x2 Adapter State → CL0 [30:30] 0x1 PM Secondary (PMS) # tbadapters -d 1 -r 0 1: Host Interface (upstream) Enabled 2: Lane 0 CL0 3: Lane 0 CL0 4: USB 3 Down Disabled 5: PCIe Down L0 6: DisplayPort IN Disabled 7: DisplayPort IN Disabled # tbadapters -d 1 -r 2 1: Lane 0 (upstream) CL0 2: Lane 1 CL0 3: Lane 0 CLd 4: Lane 1 CLd 5: Lane 0 CLd 6: Lane 1 CLd 7: Lane 0 CLd 8: Lane 1 CLd 9: PCIe Up L0 10: PCIe Down Disabled 11: DisplayPort OUT Disabled 12: DisplayPort OUT Disabled 13: Not implemented 14: Not implemented 15: Not implemented 16: Not implemented 17: PCIe Down Disabled 18: PCIe Down Disabled 19: DisplayPort OUT Disabled 20: USB 3 Up Disabled 21: USB 3 Down Disabled 22: USB 3 Down Disabled 23: USB 3 Down Disabled > Also please provide full dmesg with dynamic debugging enabled. Attached (dmesg-tb-dyndbg-20261109.txt.gz, gzipped to stay under the list size limit). It is the full log since boot; at 68136.012005 I reloaded the driver with "modprobe thunderbolt host_reset=0 dyndbg=+p" so the whole enumeration of the host routers, the retimer and the DEG2 is captured with debug output. The link came up the same way again, 2 x Gen2 ("current link speed 10.0 Gb/s", "link: TBT"). The only edits to the log are masked MAC and IP addresses. Happy to run anything else that would help. Thanks, James