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[Bug 1313981] Re: Kernel disabling serial port ttyS0 on boot

 

I am surprised the importance of this bug is only "medium". A lot of
important devices stopped working for us - contactless card readers
(ACR120), USB scanners (Canon LIDE models)... Thankfully, kernel 3.16
really does fix the issue.

For us, the bug manifested in kernels 3.2, 3.11, 3.13 using Intel
Haswell desktop and mobile chipsets (B85, H81, H87, C220) on both USB
2.0 and 3.0 ports using 32-bit or 64-bit Ubuntu 12.04 and 14.04. Kernel
3.16 fixes this on all mentioned ports, chipsets and OS versions.
Honestly, thanks a lot to everyone here, and I hope more people will
find this bug thread... and ideally that the fix will get backported to
older kernels (especially 3.13 since it's the current Ubuntu LTS one).

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https://bugs.launchpad.net/bugs/1313981

Title:
  Kernel disabling serial port ttyS0 on boot

Status in linux package in Ubuntu:
  Fix Released

Bug description:
  On boot in 13.10 kern.log would state:

   Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled
   00:0a: ttyS0 at I/O 0x3f8 (irq = 4) is a 16550A

  and my serial modem would work just fine.

  After upgrading to 14.04 the kernel log contains:

   Serial: 8250/16550 driver, 4 ports, IRQ sharing enabled
   serial 00:0a: disabled

  [[ Note that with the 3.13.0-24 kernel as reported in the bug below we see this:
  [    3.191190] Serial: 8250/16550 driver, 32 ports, IRQ sharing enabled
  [    3.191342] serial 00:0a: disabled
  ]]

  How do I enable 00:0a?  Do I need to recompile the kernel with a different config?
  ---
  ApportVersion: 2.14.1-0ubuntu3
  Architecture: amd64
  AudioDevicesInUse:
   USER        PID ACCESS COMMAND
   /dev/snd/controlC0:  ubuntu-gnome   2581 F.... pulseaudio
   /dev/snd/controlC1:  ubuntu-gnome   2581 F.... pulseaudio
  CasperVersion: 1.340
  CurrentDesktop: GNOME
  DistroRelease: Ubuntu 14.04
  LiveMediaBuild: Ubuntu-GNOME 14.04 LTS "Trusty Tahr" - Release amd64 (20140416.2)
  MachineType: System manufacturer System Product Name
  Package: linux (not installed)
  ProcEnviron:
   TERM=xterm
   PATH=(custom, no user)
   XDG_RUNTIME_DIR=<set>
   LANG=en_US.UTF-8
   SHELL=/bin/bash
  ProcFB: 0 inteldrmfb
  ProcKernelCmdLine: BOOT_IMAGE=/casper/vmlinuz.efi file=/cdrom/preseed/username.seed boot=casper quiet splash live-media=/dev/sdd1 --
  ProcVersionSignature: Ubuntu 3.13.0-24.46-generic 3.13.9
  RelatedPackageVersions:
   linux-restricted-modules-3.13.0-24-generic N/A
   linux-backports-modules-3.13.0-24-generic  N/A
   linux-firmware                             1.127
  RfKill:
   0: phy0: Wireless LAN
    Soft blocked: no
    Hard blocked: no
  Tags:  trusty
  Uname: Linux 3.13.0-24-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: adm cdrom dip lpadmin plugdev sambashare sudo
  _MarkForUpload: True
  dmi.bios.date: 08/13/2013
  dmi.bios.vendor: American Megatrends Inc.
  dmi.bios.version: 2104
  dmi.board.asset.tag: To be filled by O.E.M.
  dmi.board.name: P8Z77-V
  dmi.board.vendor: ASUSTeK COMPUTER INC.
  dmi.board.version: Rev 1.xx
  dmi.chassis.asset.tag: Asset-1234567890
  dmi.chassis.type: 3
  dmi.chassis.vendor: Chassis Manufacture
  dmi.chassis.version: Chassis Version
  dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2104:bd08/13/2013:svnSystemmanufacturer:pnSystemProductName:pvrSystemVersion:rvnASUSTeKCOMPUTERINC.:rnP8Z77-V:rvrRev1.xx:cvnChassisManufacture:ct3:cvrChassisVersion:
  dmi.product.name: System Product Name
  dmi.product.version: System Version
  dmi.sys.vendor: System manufacturer

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