Hello, Trying to use a built-in USB device I rarely use (Sierra EM7345 LTE modem), I ran into issues from the modem flapping (getting removed from USB bus before LTE network registration is visible) up to all devices on the bus being "disconnected" (xhci giving up, in my understanding, with only the root hubs listed by lsusb). Checking the syslog, I find this: May 30 17:35:46 localhost kernel: [ 278.999480] DMAR: DRHD: handling fault status reg 3 May 30 17:35:46 localhost kernel: [ 278.999485] DMAR: [DMA Read] Request device [00:16.7] PASID ffffffff fault addr 9cdff000 [fault reason 02] Present bit in context entry is clear May 30 17:35:46 localhost kernel: [ 278.999488] DMAR: DRHD: handling fault status reg 3 May 30 17:35:46 localhost kernel: [ 278.999490] DMAR: [DMA Read] Request device [00:16.7] PASID ffffffff fault addr 9cdff000 [fault reason 02] Present bit in context entry is clear May 30 17:35:46 localhost kernel: [ 279.001076] DMAR: DRHD: handling fault status reg 2 May 30 17:35:46 localhost kernel: [ 279.001078] DMAR: [DMA Write] Request device [00:16.7] PASID ffffffff fault addr 9cdff000 [fault reason 02] Present bit in context entry is clear May 30 17:35:46 localhost kernel: [ 279.001120] DMAR: DRHD: handling fault status reg 2 May 30 17:35:47 localhost kernel: [ 280.738192] usb 2-4: USB disconnect, device number 10 May 30 17:35:47 localhost kernel: [ 280.738224] cdc_mbim 2-4:1.0: Tx URB error: -19 May 30 17:35:47 localhost kernel: [ 280.738303] cdc_mbim 2-4:1.0 wwan0: unregister 'cdc_mbim' usb-0000:00:14.0-4, CDC MBIM May 30 17:35:47 localhost ModemManager[736]: <info> (net/wwan0): released by device '/sys/devices/pci0000:00/0000:00:14.0/usb2/2-4' May 30 17:35:47 localhost ModemManager[736]: [/dev/cdc-wdm0] unexpected port hangup! May 30 17:35:47 localhost ModemManager[736]: [/dev/cdc-wdm0] channel destroyed May 30 17:35:47 localhost ModemManager[736]: <info> Connection to mbim-proxy for /dev/cdc-wdm0 lost, reprobing May 30 17:35:47 localhost ModemManager[736]: <info> [device /sys/devices/pci0000:00/0000:00:14.0/usb2/2-4] creating modem with plugin 'Sierra' and '2' ports May 30 17:35:47 localhost ModemManager[736]: <warn> Could not recreate modem for device '/sys/devices/pci0000:00/0000:00:14.0/usb2/2-4': Failed to find a net port in the MBIM modem May 30 17:35:47 localhost ModemManager[736]: <info> (usbmisc/cdc-wdm0): released by device '/sys/devices/pci0000:00/0000:00:14.0/usb2/2-4' May 30 17:35:47 localhost ModemManager[736]: <info> (tty/ttyACM0): released by device '/sys/devices/pci0000:00/0000:00:14.0/usb2/2-4' May 30 17:35:48 localhost kernel: [ 281.202173] usb 2-4: new high-speed USB device number 11 using xhci_hcd May 30 17:35:48 localhost kernel: [ 281.224037] usb 2-4: New USB device found, idVendor=8087, idProduct=0716, bcdDevice= 0.00 May 30 17:35:48 localhost kernel: [ 281.224043] usb 2-4: New USB device strings: Mfr=0, Product=0, SerialNumber=0 May 30 17:35:48 localhost kernel: [ 281.225646] usb_serial_simple 2-4:1.0: flashloader converter detected May 30 17:35:48 localhost kernel: [ 281.225891] usb 2-4: flashloader converter now attached to ttyUSB0 which makes me suspect a missing IOMMU mapping in ACPI for the xhci controller. In this case, the xhci could recover and re-enumerated the device fairly quickly. Booting with "intel_iommu=off" makes the LTE modem work at least far enough that it gets registered to network (can send/receive SMS). I have not tried data communication (no data plan on current SIM). I have noticed for a while that this machine had a tendency to lose all USB devices more often than I enable the LTE modem, so it seems the modem just make this issue more likely, and is not their direct cause. This is on a 5.6.7 (Debian Sid 5.6.0-1-amd64, version from which pasted logs are extracted), and reproduced with 5.6.14 (Debian Sid 5.6.0-2-amd64). The USB issues have been happening for a long time, and I use this modem rarely enough that I would not notice a new issue before several kernel versions. The modem usually worked "well enough" but always has had a bit of flapping, sometimes working after one or two suspend/resume cycles, and until now I did not feel the need to investigate more (I assumed a less-than-optimal modem/modem driver). This time it never ended up working after several suspend/resume cycles and reboots. So I do not believe it is a localised regression, but a bad situation getting just nudged over the edge. $ lspci 00:00.0 Host bridge: Intel Corporation Broadwell-U Host Bridge -OPI (rev 09) 00:02.0 VGA compatible controller: Intel Corporation HD Graphics 5500 (rev 09) 00:03.0 Audio device: Intel Corporation Broadwell-U Audio Controller (rev 09) 00:14.0 USB controller: Intel Corporation Wildcat Point-LP USB xHCI Controller (rev 03) 00:16.0 Communication controller: Intel Corporation Wildcat Point-LP MEI Controller #1 (rev 03) 00:19.0 Ethernet controller: Intel Corporation Ethernet Connection (3) I218-V (rev 03) 00:1b.0 Audio device: Intel Corporation Wildcat Point-LP High Definition Audio Controller (rev 03) 00:1c.0 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #6 (rev e3) 00:1c.1 PCI bridge: Intel Corporation Wildcat Point-LP PCI Express Root Port #3 (rev e3) 00:1d.0 USB controller: Intel Corporation Wildcat Point-LP USB EHCI Controller (rev 03) 00:1f.0 ISA bridge: Intel Corporation Wildcat Point-LP LPC Controller (rev 03) 00:1f.2 SATA controller: Intel Corporation Wildcat Point-LP SATA Controller [AHCI Mode] (rev 03) 00:1f.3 SMBus: Intel Corporation Wildcat Point-LP SMBus Controller (rev 03) 00:1f.6 Signal processing controller: Intel Corporation Wildcat Point-LP Thermal Management Controller (rev 03) 02:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS5227 PCI Express Card Reader (rev 01) 03:00.0 Network controller: Intel Corporation Wireless 7265 (rev 59) $ lsusb Bus 001 Device 002: ID 8087:8001 Intel Corp. Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 003 Device 001: ID 1d6b:0003 Linux Foundation 3.0 root hub Bus 002 Device 006: ID 04f2:b449 Chicony Electronics Co., Ltd Integrated Camera Bus 002 Device 017: ID 8087:0a2a Intel Corp. Bus 002 Device 004: ID 138a:0017 Validity Sensors, Inc. VFS 5011 fingerprint sensor Bus 002 Device 003: ID 058f:9540 Alcor Micro Corp. AU9540 Smartcard Reader Bus 002 Device 016: ID 1199:a001 Sierra Wireless, Inc. Sierra Wireless EM7345 4G LTE Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Early boot messages are unhappy with firmware (1.37 is the latest available version to date): May 30 17:32:17 localhost kernel: [ 0.168626] DMAR: Host address width 39 May 30 17:32:17 localhost kernel: [ 0.168629] DMAR: DRHD base: 0x000000fed90000 flags: 0x0 May 30 17:32:17 localhost kernel: [ 0.168640] DMAR: dmar0: reg_base_addr fed90000 ver 1:0 cap 1c0000c40660462 ecap 7e1ff0505e May 30 17:32:17 localhost kernel: [ 0.168643] DMAR: DRHD base: 0x000000fed91000 flags: 0x1 May 30 17:32:17 localhost kernel: [ 0.168651] DMAR: dmar1: reg_base_addr fed91000 ver 1:0 cap d2008c20660462 ecap f010da May 30 17:32:17 localhost kernel: [ 0.168653] DMAR: RMRR base: 0x0000009c0f1000 end: 0x0000009c107fff May 30 17:32:17 localhost kernel: [ 0.168655] DMAR: RMRR base: 0x0000009d800000 end: 0x0000009fffffff May 30 17:32:17 localhost kernel: [ 0.168658] DMAR: [Firmware Bug]: No firmware reserved region can cover this RMRR [0x000000009d800000-0x000000009fffffff], contact BIOS vendor for fixes May 30 17:32:17 localhost kernel: [ 0.168671] DMAR: [Firmware Bug]: Your BIOS is broken; bad RMRR [0x000000009d800000-0x000000009fffffff] May 30 17:32:17 localhost kernel: [ 0.168671] BIOS vendor: LENOVO; Ver: JBET73WW (1.37 ); Product Version: ThinkPad T450s May 30 17:32:17 localhost kernel: [ 0.168675] DMAR-IR: IOAPIC id 2 under DRHD base 0xfed91000 IOMMU 1 May 30 17:32:17 localhost kernel: [ 0.168677] DMAR-IR: HPET id 0 under DRHD base 0xfed91000 May 30 17:32:17 localhost kernel: [ 0.168679] DMAR-IR: x2apic is disabled because BIOS sets x2apic opt out bit. May 30 17:32:17 localhost kernel: [ 0.168680] DMAR-IR: Use 'intremap=no_x2apic_optout' to override the BIOS setting. May 30 17:32:17 localhost kernel: [ 0.169608] DMAR-IR: Enabled IRQ remapping in xapic mode [...] May 30 17:32:17 localhost kernel: [ 0.890456] pci 0000:00:02.0: DMAR: Disabling IOMMU for graphics on this chipset [...] May 30 17:32:17 localhost kernel: [ 2.574095] DMAR: No ATSR found May 30 17:32:17 localhost kernel: [ 2.574207] DMAR: dmar1: Using Queued invalidation May 30 17:32:17 localhost kernel: [ 2.574608] pci 0000:00:00.0: Adding to iommu group 0 May 30 17:32:17 localhost kernel: [ 2.574760] pci 0000:00:03.0: Adding to iommu group 1 May 30 17:32:17 localhost kernel: [ 2.575002] pci 0000:00:14.0: Adding to iommu group 2 May 30 17:32:17 localhost kernel: [ 2.575170] pci 0000:00:16.0: Adding to iommu group 3 May 30 17:32:17 localhost kernel: [ 2.575339] pci 0000:00:19.0: Adding to iommu group 4 May 30 17:32:17 localhost kernel: [ 2.575489] pci 0000:00:1b.0: Adding to iommu group 5 May 30 17:32:17 localhost kernel: [ 2.575652] pci 0000:00:1c.0: Adding to iommu group 6 May 30 17:32:17 localhost kernel: [ 2.575818] pci 0000:00:1c.1: Adding to iommu group 7 May 30 17:32:17 localhost kernel: [ 2.576035] pci 0000:00:1d.0: Adding to iommu group 8 May 30 17:32:17 localhost kernel: [ 2.580374] pci 0000:00:1f.0: Adding to iommu group 9 May 30 17:32:17 localhost kernel: [ 2.580411] pci 0000:00:1f.2: Adding to iommu group 9 May 30 17:32:17 localhost kernel: [ 2.580436] pci 0000:00:1f.3: Adding to iommu group 9 May 30 17:32:17 localhost kernel: [ 2.580461] pci 0000:00:1f.6: Adding to iommu group 9 May 30 17:32:17 localhost kernel: [ 2.580628] pci 0000:02:00.0: Adding to iommu group 10 May 30 17:32:17 localhost kernel: [ 2.581050] pci 0000:03:00.0: Adding to iommu group 11 May 30 17:32:17 localhost kernel: [ 2.581056] DMAR: Intel(R) Virtualization Technology for Directed I/O I am not sure what could fix this issue, hence the many recipients for this email: - An xhci module issue (should check/define extra IOMMU mappings, warn about them missing, or maybe be able to more reliably recover) ? - A new IOMMU quirk (workaround bad firmware) ? - A new thinkpad_acpi quirk (workaround bad firmware) ? Or somewhere else that I did not think of ? Hopefully it will not require a Lenovo BIOS fix, as this is an aging model. Regards, -- Vincent Pelletier
