Comment 0 for bug 1090715

I have been troubleshooting an interesting bug on my Toshiba L840 laptop for a number of months now. This bug affects all versions of Ubuntu since (and including) 12.04 and other Linux distributions as well (so this is most likely an upstream bug). I have only ran the 32-bit version with PAE support because I choose application compatibility and efficient memory usage over what 64-bit Linux can provide.

Here is what I have experienced:

Every kernel version I have tried is affected by this bug since 3.2 in Precise (kernel 3.3 - 3.7 is affected). What happens is my hard drive write performance is greatly reduced (and over time it becomes so slow it is unusable) once I run a newer version of Linux kernel. The stock kernel of Precise does not have this bug but it has too many other bugs that cause hard lockups on ivy bridge so I cannot use it. I am happy to report that the hard lockups seem to have disappeared on 13.04 (Linux kernel 3.7) and the most stable experience I have had so far is with kernel version 3.7.0-5 on Raring 32-bit.

Even though I have found a relatively stable experience running Raring I am still haunted by this write performance issue. Once I boot I can get consistent write speeds at about 40MB/s (which is about half the speed of what my drive is able to write at) and read speed never really seems to be affected. Here is a test using dd to check write speed:

owner@Satellite-L840:~$ dd if=/dev/zero of=/tmp/output bs=8k count=50k; rm -f /tmp/output
51200+0 records in
51200+0 records out
419430400 bytes (419 MB) copied, 10.6863 s, 39.2 MB/s
owner@Satellite-L840:~$ dd if=/dev/zero of=/tmp/output bs=8k count=50k; rm -f /tmp/output
51200+0 records in
51200+0 records out
419430400 bytes (419 MB) copied, 10.4765 s, 40.0 MB/s
owner@Satellite-L840:~$ dd if=/dev/zero of=/tmp/output bs=8k count=50k; rm -f /tmp/output
51200+0 records in
51200+0 records out
419430400 bytes (419 MB) copied, 10.4648 s, 40.1 MB/s
owner@Satellite-L840:~$ dd if=/dev/zero of=/tmp/output bs=8k count=50k; rm -f /tmp/output
51200+0 records in
51200+0 records out
419430400 bytes (419 MB) copied, 11.2678 s, 37.2 MB/s

Even though 40MB/s write speed is completely unacceptable I would actually be okay with it if it didn't drop any lower than this but eventually it does.

I have experienced that over time eventually the write speed of the drive will drop to about 1-2MB/s and at that point the computer becomes unusable and has to be rebooted.

Strangely enough I have finally noticed that the significant drop from 40MB/s to 1-2MB/s seems to be triggered by certain applications, for instance when I have a torrent downloading using various torrent downloader programs, I have experienced this bug more frequently.

Even so, if I choose to not use the torrent downloading programs the bug will eventually crop back up (could be hours, could be several days...) but eventually it happens and I have to reboot.

Here are some more troubleshooting steps I have tried in a failed attempt to isolate the issue:
* I have ran memtest 86+ for over 24 hours on my laptop and it completed without error
* I have scanned my hard drive using mhdd and no bad sectors
* I have replaced my hard drive with a different size and different brand hard drive and same issue
* I have attempted a clean install of Precise and then updating to the latest packages and then install the Quantal kernel from the stable repositories and reboot. Immediately this bug affects my computer
* I have installed a clean install of 13.04 and bug still exists
* I have tried installing Ubuntu (12.04 and 13.04 32-bit) on a flash drive to see if the bug crops up eventually on the flash drive and it does. Eventually the write speed even to the USB bus will drop to 1-2MB/s !!!
* I have even tried installing other distributions as well (Fedora and Debian) and they both have the same issue.

One more thing worth noting: The very first kernel release that I tried in 13.04 was 3.7.0-2 and even now if I reboot and choose that kernel I get better write performance at first (70-80MB/s) but eventually the write speed drops down to 1-2 MB/s just like the others.

I have experienced many problems running Linux on this laptop but even so it is the fastest and best performing computer experience I have ever had. Now that the lockups are gone I feel so close to getting this computer working perfectly with Linux but I need help from someone with troubleshooting this issue further.

ProblemType: Bug
DistroRelease: Ubuntu 13.04
Package: linux-image 3.7.0.6.10
ProcVersionSignature: Ubuntu 3.7.0-5.13-generic 3.7.0-rc8
Uname: Linux 3.7.0-5-generic i686
ApportVersion: 2.7-0ubuntu2
Architecture: i386
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/controlC0: acjohnson 2197 F.... pulseaudio
Date: Sat Dec 15 07:13:04 2012
HibernationDevice: RESUME=UUID=9f7c92ad-121c-458f-8813-1cb8191180c2
InstallationDate: Installed on 2012-12-10 (5 days ago)
InstallationMedia: Ubuntu 13.04 "Raring Ringtail" - Alpha i386 (20121206)
MachineType: TOSHIBA Satellite L840
MarkForUpload: True
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=/boot/vmlinuz-3.7.0-5-generic root=UUID=4836d385-16fc-47c0-8720-c369e39d0775 ro quiet splash i915.i915_enable_rc6=7 vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-3.7.0-5-generic N/A
 linux-backports-modules-3.7.0-5-generic N/A
 linux-firmware 1.98
SourcePackage: linux
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 06/26/2012
dmi.bios.vendor: Insyde Corp.
dmi.bios.version: 1.80
dmi.board.asset.tag: Type2 - Board Asset Tag
dmi.board.name: Type2 - Board Product Name1
dmi.board.vendor: Type2 - Board Vendor Name1
dmi.board.version: Type2 - Board Version
dmi.chassis.asset.tag: No Asset Tag
dmi.chassis.type: 10
dmi.chassis.vendor: OEM Chassis Manufacturer
dmi.chassis.version: OEM Chassis Version
dmi.modalias: dmi:bvnInsydeCorp.:bvr1.80:bd06/26/2012:svnTOSHIBA:pnSatelliteL840:pvrPSK8GU-08S00D:rvnType2-BoardVendorName1:rnType2-BoardProductName1:rvrType2-BoardVersion:cvnOEMChassisManufacturer:ct10:cvrOEMChassisVersion:
dmi.product.name: Satellite L840
dmi.product.version: PSK8GU-08S00D
dmi.sys.vendor: TOSHIBA