Hi,
I am seeing this problem with linux-image-4.15.0-0.bpo.2-amd64 4.15.11-1~bpo9+1 amd64 and firmware-iwlwifi 20170823-1~bpo9+1, and with their counterparts from Stable on my XPS 13 from around 2013. FWIW, on some networks, I have no trouble connecting, but on others, it just won't work at all. I've tried this backport version after losing connectivity with the stable package. $ journalctl -b 0 | grep iwlwifi | head Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: can't disable ASPM; OS doesn't have ASPM control Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: firmware: direct-loading firmware iwlwifi-6000g2b-6.ucode Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: loaded firmware version 18.168.6.1 op_mode iwldvm Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: CONFIG_IWLWIFI_DEBUG disabled Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: CONFIG_IWLWIFI_DEBUGFS disabled Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: CONFIG_IWLWIFI_DEVICE_TRACING disabled Apr 30 23:27:08 debian kernel: iwlwifi 0000:01:00.0: Detected Intel(R) Centrino(R) Advanced-N 6235 AGN, REV=0xB0 Apr 30 23:27:09 debian kernel: iwlwifi 0000:01:00.0: Radio type=0x2-0x1-0x0 Apr 30 23:27:09 debian kernel: iwlwifi 0000:01:00.0: Radio type=0x2-0x1-0x0 Apr 30 23:27:38 debian kernel: iwlwifi 0000:01:00.0: Radio type=0x2-0x1-0x0 $ iwconfig wlan0 wlan0 IEEE 802.11 ESSID:off/any Mode:Managed Frequency:5.22 GHz Access Point: Not-Associated Tx-Power=15 dBm Retry short limit:7 RTS thr:off Fragment thr:off Power Management:off Here's one such section from the logs, I get them every few seconds: Apr 30 23:43:30 debian kernel: [ 995.983609] ieee80211 phy0: Hardware restart was requested Apr 30 23:43:30 debian kernel: [ 995.996648] iwlwifi 0000:01:00.0: Radio type=0x2-0x1-0x0 Apr 30 23:43:30 debian kernel: [ 996.297641] iwlwifi 0000:01:00.0: Radio type=0x2-0x1-0x0 Apr 30 23:43:38 debian kernel: [ 1003.669572] iwlwifi 0000:01:00.0: Microcode SW error detected. Restarting 0x2000000. Apr 30 23:43:38 debian kernel: [ 1003.669589] iwlwifi 0000:01:00.0: Loaded firmware version: 18.168.6.1 Apr 30 23:43:38 debian kernel: [ 1003.669781] iwlwifi 0000:01:00.0: Start IWL Error Log Dump: Apr 30 23:43:38 debian kernel: [ 1003.669789] iwlwifi 0000:01:00.0: Status: 0x0000004C, count: 6 Apr 30 23:43:38 debian kernel: [ 1003.669797] iwlwifi 0000:01:00.0: 0x00000034 | NMI_INTERRUPT_WDG Apr 30 23:43:38 debian kernel: [ 1003.669803] iwlwifi 0000:01:00.0: 0x00010564 | uPc Apr 30 23:43:38 debian kernel: [ 1003.669810] iwlwifi 0000:01:00.0: 0x0001054E | branchlink1 Apr 30 23:43:38 debian kernel: [ 1003.669816] iwlwifi 0000:01:00.0: 0x00010580 | branchlink2 Apr 30 23:43:38 debian kernel: [ 1003.669824] iwlwifi 0000:01:00.0: 0x0000DBEA | interruptlink1 Apr 30 23:43:38 debian kernel: [ 1003.669831] iwlwifi 0000:01:00.0: 0x0001CB38 | interruptlink2 Apr 30 23:43:38 debian kernel: [ 1003.669837] iwlwifi 0000:01:00.0: 0x00000002 | data1 Apr 30 23:43:38 debian kernel: [ 1003.669844] iwlwifi 0000:01:00.0: 0x07030000 | data2 Apr 30 23:43:38 debian kernel: [ 1003.669851] iwlwifi 0000:01:00.0: 0x0002617C | line Apr 30 23:43:38 debian kernel: [ 1003.669858] iwlwifi 0000:01:00.0: 0x11C0121E | beacon time Apr 30 23:43:38 debian kernel: [ 1003.669865] iwlwifi 0000:01:00.0: 0x9B5B2DE2 | tsf low Apr 30 23:43:38 debian kernel: [ 1003.669871] iwlwifi 0000:01:00.0: 0x00000055 | tsf hi Apr 30 23:43:38 debian kernel: [ 1003.669876] iwlwifi 0000:01:00.0: 0x00000000 | time gp1 Apr 30 23:43:38 debian kernel: [ 1003.669882] iwlwifi 0000:01:00.0: 0x0070585B | time gp2 Apr 30 23:43:38 debian kernel: [ 1003.669889] iwlwifi 0000:01:00.0: 0x00000000 | time gp3 Apr 30 23:43:38 debian kernel: [ 1003.669896] iwlwifi 0000:01:00.0: 0x754312A8 | uCode version Apr 30 23:43:38 debian kernel: [ 1003.669905] iwlwifi 0000:01:00.0: 0x000000B0 | hw version Apr 30 23:43:38 debian kernel: [ 1003.669911] iwlwifi 0000:01:00.0: 0x00484B00 | board version Apr 30 23:43:38 debian kernel: [ 1003.669918] iwlwifi 0000:01:00.0: 0x0207001C | hcmd Apr 30 23:43:38 debian kernel: [ 1003.669924] iwlwifi 0000:01:00.0: 0xA7863002 | isr0 Apr 30 23:43:38 debian kernel: [ 1003.669930] iwlwifi 0000:01:00.0: 0x11898000 | isr1 Apr 30 23:43:38 debian kernel: [ 1003.669935] iwlwifi 0000:01:00.0: 0x00000E17 | isr2 Apr 30 23:43:38 debian kernel: [ 1003.669941] iwlwifi 0000:01:00.0: 0x8543FCC0 | isr3 Apr 30 23:43:38 debian kernel: [ 1003.669947] iwlwifi 0000:01:00.0: 0x00000000 | isr4 Apr 30 23:43:38 debian kernel: [ 1003.669954] iwlwifi 0000:01:00.0: 0x00804110 | isr_pref Apr 30 23:43:38 debian kernel: [ 1003.669961] iwlwifi 0000:01:00.0: 0x0002617C | wait_event Apr 30 23:43:38 debian kernel: [ 1003.669969] iwlwifi 0000:01:00.0: 0x000000B4 | l2p_control Apr 30 23:43:38 debian kernel: [ 1003.669976] iwlwifi 0000:01:00.0: 0x000000A4 | l2p_duration Apr 30 23:43:38 debian kernel: [ 1003.669983] iwlwifi 0000:01:00.0: 0x0000000F | l2p_mhvalid Apr 30 23:43:38 debian kernel: [ 1003.669989] iwlwifi 0000:01:00.0: 0x001050C0 | l2p_addr_match Apr 30 23:43:38 debian kernel: [ 1003.669996] iwlwifi 0000:01:00.0: 0x00000005 | lmpm_pmg_sel Apr 30 23:43:38 debian kernel: [ 1003.670004] iwlwifi 0000:01:00.0: 0x13011136 | timestamp Apr 30 23:43:38 debian kernel: [ 1003.670009] iwlwifi 0000:01:00.0: 0x0000A8C0 | flow_handler Apr 30 23:43:38 debian kernel: [ 1003.670105] iwlwifi 0000:01:00.0: Start IWL Event Log Dump: display last 1 entries Apr 30 23:43:38 debian kernel: [ 1003.670160] iwlwifi 0000:01:00.0: EVT_LOGT:0007362647:0x0000010c:0123 Apr 30 23:43:38 debian kernel: [ 1003.682688] ieee80211 phy0: Hardware restart was requested Cheers, Toni -- System Information: Debian Release: 9.4 APT prefers stable APT policy: (990, 'stable'), (500, 'unstable'), (500, 'testing') Architecture: amd64 (x86_64) Foreign Architectures: i386 Kernel: Linux 4.15.0-0.bpo.2-amd64 (SMP w/4 CPU cores) Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.utf8 (charmap=UTF-8), LANGUAGE=en_US:en (charmap=UTF-8) Shell: /bin/sh linked to /bin/dash Init: systemd (via /run/systemd/system) firmware-iwlwifi depends on no packages. firmware-iwlwifi recommends no packages. Versions of packages firmware-iwlwifi suggests: ii initramfs-tools 0.130 -- no debconf information $ lspci 00:00.0 Host bridge: Intel Corporation 3rd Gen Core processor DRAM Controller (rev 09) 00:02.0 VGA compatible controller: Intel Corporation 3rd Gen Core processor Graphics Controller (rev 09) 00:14.0 USB controller: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller (rev 04) 00:16.0 Communication controller: Intel Corporation 7 Series/C216 Chipset Family MEI Controller #1 (rev 04) 00:1a.0 USB controller: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #2 (rev 04) 00:1b.0 Audio device: Intel Corporation 7 Series/C216 Chipset Family High Definition Audio Controller (rev 04) 00:1c.0 PCI bridge: Intel Corporation 7 Series/C216 Chipset Family PCI Express Root Port 1 (rev c4) 00:1d.0 USB controller: Intel Corporation 7 Series/C216 Chipset Family USB Enhanced Host Controller #1 (rev 04) 00:1f.0 ISA bridge: Intel Corporation QS77 Express Chipset LPC Controller (rev 04) 00:1f.2 SATA controller: Intel Corporation 7 Series Chipset Family 6-port SATA Controller [AHCI mode] (rev 04) 00:1f.3 SMBus: Intel Corporation 7 Series/C216 Chipset Family SMBus Controller (rev 04) 01:00.0 Network controller: Intel Corporation Centrino Advanced-N 6235 (rev 24)