----- Forwarded message from bugzilla-daemon@xxxxxxxxxxxxxxxxxxx ----- Date: Fri, 15 Dec 2017 22:24:36 +0000 From: bugzilla-daemon@xxxxxxxxxxxxxxxxxxx To: bugzilla.pci@xxxxxxxxx Subject: [Bug 198171] New: [AMD][X399] Inconsistent PCIe lane linking count https://bugzilla.kernel.org/show_bug.cgi?id=198171 Bug ID: 198171 Summary: [AMD][X399] Inconsistent PCIe lane linking count Product: Drivers Version: 2.5 Kernel Version: 4.15-rc3 Hardware: x86-64 OS: Linux Tree: Mainline Status: NEW Severity: normal Priority: P1 Component: PCI Assignee: drivers_pci@xxxxxxxxxxxxxxxxxxxx Reporter: barry@xxxxxxxxxxxxx Regression: No I have an AMD Threadripper system with an MSI X399 gaming carbon pro motherboard and a 1900X CPU. When it boots, sometimes one of my cards (Intel X550 NIC) initializes X1 link trained and sometimes it link trains at X4. I have tried this card in various other (Intel based) systems and not experienced this issue. I am uncertain if this is a Bios issue, PCIe driver issue, or something else. I am running the latest MB bios revision (V16 as of this writing). In general, it seems like cold boots come up with a X1 width for the LnkSta and warm reboots come up with X4 width for the LnkSta. This is not absolute though, as I have observed both inversions. I will attach complete outputs but here are the highlights: $ diff x550.{good,bad} 31c31 < LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- --- > LnkSta: Speed 8GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- > BWMgmt- ABWMgmt- Note that LnkCap always reports x4. $ diff lspci.all.{good,bad} [00:03.4 PCI bridge: Advanced Micro Devices, Inc. [AMD] Device 1453 (prog-if 00 [Normal decode])] 295c295 < LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive+ BWMgmt+ ABWMgmt- --- > LnkSta: Speed 8GT/s, Width x1, TrErr- Train- SlotClk+ DLActive+ > BWMgmt+ ABWMgmt- [0b:00.0 Serial Attached SCSI controller: LSI Logic / Symbios Logic SAS3008 PCI-Express Fusion-MPT SAS-3 (rev 02)] 1414c1414 < HeaderLog: 04000001 0000200f 0b070000 b4456d62 --- > HeaderLog: 04000001 0000210f 0b070000 119631a9 [0c:00.0 Ethernet controller: Intel Corporation Ethernet Controller 10G X550T (rev 01)] 1454c1454 < LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- --- > LnkSta: Speed 8GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- > BWMgmt- ABWMgmt- [0c:00.1 Ethernet controller: Intel Corporation Ethernet Controller 10G X550T (rev 01)] 1529c1529 < LnkSta: Speed 8GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt- --- > LnkSta: Speed 8GT/s, Width x1, TrErr- Train- SlotClk+ DLActive- > BWMgmt- ABWMgmt- This system is new and the video card that is currently in it requires the AMD DC patch set that was accepted in the 4.15-rc1 cycle. As such, I have no prior data for this configuration. I am open to installing another video card and trying older kernel versions if it would help. -- You are receiving this mail because: You are watching the assignee of the bug. ----- End forwarded message ----- There are some native host bridge drivers that do things with link training, but you're using the ACPI host bridge driver, which doesn't touch that, and the PCI core itself doesn't do anything in that area either. My guess is there something in the BIOS that is responsible for the difference. Bjorn
