<SOLVED> "no caching mode page found" Is this a Problem?

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Reljoy
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<SOLVED> "no caching mode page found" Is this a Problem?

Post by Reljoy »

I've been getting this warning for some time now on boot-up. The computer works fine.

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[ 3.149617] sd 6:0:0:0: [sdc] No Caching mode page found
[ 3.149632] sd 6:0:0:0: [sdc] Assuming drive cache: write through
Image here...
https://share.internxt.com/d/s/file/909 ... d21ec3b2b3

1. Am I right in thinking that I can safely ignore this? Or should I do something about it?
2. Could it be related to my computer occasionally not booting (nothing showing on the monitor after several minutes) - or is that a separate issue likely related to the power supply?
Thanks.

EDIT: I just realised that I only get this warning if my external USB hard drive is connected. It is virtually always connected.

Linux Mint 20.3 Mate

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~ $ sudo fdisk -l
Disk /dev/sdc: 3.65 TiB, 4000787030016 bytes, 7814037168 sectors
Disk model: WDC WD40EZRZ-00G
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disklabel type: gpt
Disk identifier: 42265DB1-F135-4C4B-8824-C970877BAC67

Device         Start        End    Sectors   Size Type
/dev/sdc1         34     262177     262144   128M Microsoft reserved
/dev/sdc2     264192  512264191  512000000 244.1G Microsoft basic data
/dev/sdc3  512264192 7814035455 7301771264   3.4T Linux filesystem

Partition 1 does not start on physical sector boundary.

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~ $ inxi -Fxxxrz
System:    Kernel: 5.15.0-58-generic x86_64 bits: 64 compiler: N/A Desktop: MATE 1.26.0 info: mate-panel wm: Compiz 0.9.14.1 
           dm: LightDM 1.30.0 Distro: Linux Mint 20.3 Una base: Ubuntu 20.04 focal 
Machine:   Type: Desktop System: Gigabyte product: N/A v: N/A serial: <filter> Chassis: type: 3 serial: <filter> 
           Mobo: Gigabyte model: 970A-D3P v: x.x serial: <filter> UEFI: American Megatrends v: FC date: 06/01/2015 
CPU:       Topology: 8-Core model: AMD FX-8350 bits: 64 type: MCP arch: Bulldozer L2 cache: 2048 KiB 
           flags: avx lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 64291 
           Speed: 1406 MHz min/max: 1400/4000 MHz boost: enabled Core speeds (MHz): 1: 1406 2: 2339 3: 1424 4: 1405 5: 1406 
           6: 1406 7: 1422 8: 1418 
Graphics:  Device-1: NVIDIA GF108 [GeForce GT 730] vendor: Gigabyte driver: nvidia v: 390.157 bus ID: 01:00.0 
           chip ID: 10de:0f02 
           Display: x11 server: X.Org 1.20.13 driver: nvidia unloaded: fbdev,modesetting,nouveau,vesa compositor: compiz 
           v: 0.9.14.1 resolution: 1920x1080~60Hz 
           OpenGL: renderer: GeForce GT 730/PCIe/SSE2 v: 4.6.0 NVIDIA 390.157 direct render: Yes 
Audio:     Device-1: Advanced Micro Devices [AMD/ATI] SBx00 Azalia vendor: Gigabyte driver: snd_hda_intel v: kernel 
           bus ID: 00:14.2 chip ID: 1002:4383 
           Device-2: NVIDIA GF108 High Definition Audio vendor: Gigabyte driver: snd_hda_intel v: kernel bus ID: 01:00.1 
           chip ID: 10de:0bea 
           Sound Server: ALSA v: k5.15.0-58-generic 
Network:   Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Gigabyte driver: r8169 v: kernel 
           port: d000 bus ID: 03:00.0 chip ID: 10ec:8168 
           IF: enp3s0 state: up speed: 1000 Mbps duplex: full mac: <filter> 
           Device-2: Ralink MT7601U Wireless Adapter type: USB driver: mt7601u bus ID: 1-5:3 chip ID: 148f:7601 
           serial: <filter> 
           IF: wlxe84e065a16f9 state: up mac: <filter> 
Drives:    Local Storage: total: 11.03 TiB used: 7.92 TiB (71.9%) 
           ID-1: /dev/sda vendor: Seagate model: ST2000DM001-1CH164 size: 1.82 TiB speed: <unknown> rotation: 7200 rpm 
           serial: <filter> rev: CC27 scheme: MBR 
           ID-2: /dev/sdb vendor: Kingston model: SUV400S37120G size: 111.79 GiB speed: <unknown> serial: <filter> rev: 87RA 
           scheme: GPT 
           ID-3: /dev/sdc vendor: Western Digital model: WD40EZRZ-00GXCB0 size: 3.64 TiB speed: 6.0 Gb/s rotation: 5400 rpm 
           serial: <filter> rev: 0A80 scheme: GPT 
           ID-4: /dev/sdd type: USB vendor: Western Digital model: WD Elements 25A3 size: 5.46 TiB serial: <filter> rev: 1021 
           scheme: GPT 
Partition: ID-1: / size: 48.14 GiB used: 21.52 GiB (44.7%) fs: ext4 dev: /dev/sdb6 
           ID-2: /home size: 3.35 TiB used: 2.92 TiB (87.4%) fs: ext4 dev: /dev/sdc3 
           ID-3: swap-1 size: 3.98 GiB used: 0 KiB (0.0%) fs: swap dev: /dev/sdb7 
Sensors:   System Temperatures: cpu: 27.1 C mobo: N/A gpu: nvidia temp: 44 C 
           Fan Speeds (RPM): N/A gpu: nvidia fan: 44% 
Repos:     No active apt repos in: /etc/apt/sources.list 
           Active apt repos in: /etc/apt/sources.list.d/additional-repositories.list 
           1: deb https://dl.winehq.org/wine-builds/ubuntu/ focal main
           Active apt repos in: /etc/apt/sources.list.d/google-chrome.list 
           1: deb [arch=amd64] https://dl.google.com/linux/chrome/deb/ stable main
           Active apt repos in: /etc/apt/sources.list.d/official-package-repositories.list 
           1: deb https://mirror.aarnet.edu.au/pub/linuxmint-packages una main upstream import backport
           2: deb http://mirror.aarnet.edu.au/pub/ubuntu/archive focal main restricted universe multiverse
           3: deb http://mirror.aarnet.edu.au/pub/ubuntu/archive focal-updates main restricted universe multiverse
           4: deb http://mirror.aarnet.edu.au/pub/ubuntu/archive focal-backports main restricted universe multiverse
           5: deb http://security.ubuntu.com/ubuntu/ focal-security main restricted universe multiverse
           6: deb http://archive.canonical.com/ubuntu/ focal partner
           Active apt repos in: /etc/apt/sources.list.d/rvm-smplayer-focal.list 
           1: deb http://ppa.launchpad.net/rvm/smplayer/ubuntu focal main
           Active apt repos in: /etc/apt/sources.list.d/virtualbox.list 
           1: deb [arch=amd64] http://download.virtualbox.org/virtualbox/debian focal contrib
           Active apt repos in: /etc/apt/sources.list.d/vscode.list 
           1: deb [arch=amd64,arm64,armhf] http://packages.microsoft.com/repos/code stable main
Info:      Processes: 270 Uptime: 1h 08m Memory: 15.59 GiB used: 3.35 GiB (21.5%) Init: systemd v: 245 runlevel: 5 Compilers: 
           gcc: 9.4.0 alt: 9 Shell: bash v: 5.0.17 running in: mate-terminal inxi: 3.0.38 
Last edited by LockBot on Tue Aug 01, 2023 10:00 pm, edited 3 times in total.
Reason: Topic automatically closed 6 months after creation. New replies are no longer allowed.
mikeflan
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Re: "no caching mode page found" Is this a Problem?

Post by mikeflan »

I say you can safely ignore that error message.
We'll see if anybody else has a different opinion.
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Reljoy
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Re: "no caching mode page found" Is this a Problem?

Post by Reljoy »

Thanks, I've been ignoring it for months. I think it is because the USB hard drive does not have cache.
rene
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Re: "no caching mode page found" Is this a Problem?

Post by rene »

Reljoy wrote: Thu Feb 02, 2023 7:29 am I think it is because the USB hard drive does not have cache.
The warning is normal for USB. The disk does (generally and here) have cache: the warning is saying that kernel can not determine if said cache is write-back or write-trough even though it's treating it as write-through.

A write-through cache you can see as a read-cache: an on-device RAM based cache still lives between the drive's host-interface and the eventual backing-store -- the platters in the case of an HDD -- but a write streams right through the cache to said backing-store and is only signaled to be complete when the data is in fact safe and sound on backing store. A subsequent read of the same data still finds it in on-device RAM so it is retrieved much faster, but writes don't gain.

A write-back cache is one in which writes complete as soon as the device has the data in its cache, with the device itself flushing it to backing store when it sees fit. This of course may dramatically speed up writes from the host's point of view -- but if power is lost before the device in fact got around to flushing, the data is lost.

This is what the warning is warning about. I.e., while a drive cache being write-through or write-back is information available from an e.g. ATA drive it's here saying that it could not in this USB case obtain that information but that it's still treating the drive as having a write-through cache, i.e., is not explicitly flushing things from the side of the host (which would be a tremendous performance issue), i.e., is telling you to please not yank power from the device too suddenly if it turns out the device in fact has a write-back cache.

Not to worry; the drive will have e.g. a few capacitors with enough capacity to flush also a write-back cache when power fails and all is generally fine. Kernel still believes that you should be warned but if you disagree: if you boot with the loglevel=3 kernel-parameter the warning only goes to the log and not anymore the console. A kernel parameter you add as viewtopic.php?t=349669

P.S. I do by the way in the above believe to see that /dev/sdc, the WDC WD40EZRZ, is not USB-connected and in that case the warning while undoubtedly still not too relevant is not in fact normal. For USB and e.g. SD-cards and the like it is...
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Reljoy
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Re: "no caching mode page found" Is this a Problem?

Post by Reljoy »

Thank you Rene for your detailed reply.
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