5.4. Felsök installationsprocessen

5.4.1. Reliability of optical media

Sometimes, especially with older drives, the installer may fail to boot from an optical disc. The installer may also — even after booting successfully from such disc — fail to recognize the disc or return errors while reading from it during the installation.

Det finns många olika möjliga orsaker till dessa problem. Vi kan endast lista några vanliga problem och tillhandahålla allmänna förslag på hur man hanterar dem. Resten är upp till dig.

Det finns två mycket enkla saker som du bör prova först.

  • If the disc does not boot, check that it was inserted correctly and that it is not dirty.

  • If the installer fails to recognize the disc, try just running the option Detect and mount installation media a second time. Some DMA related issues with very old CD-ROM drives are known to be resolved in this way.

If this does not work, then try the suggestions in the subsections below. Most, but not all, suggestions discussed there are valid for CD-ROM and DVD.

If you cannot get the installation working from optical disc, try one of the other installation methods that are available.

5.4.1.1. Vanliga problem

  • Några äldre cd-rom-enheter saknar stöd för att läsa från skivor som blev brända med höga hastigheter med en modern cd-brännare.

  • Some very old CD-ROM drives do not work correctly if direct memory access (DMA) is enabled for them.

5.4.1.2. Hur man undersöker och kanske även löser problem

If the optical disc fails to boot, try the suggestions listed below.

  • Check that your BIOS actually supports booting from optical disc (only an issue for very old systems) and that booting from such media is enabled in the BIOS.

  • If you downloaded an iso image, check that the md5sum of that image matches the one listed for the image in the MD5SUMS file that should be present in the same location as where you downloaded the image from.

    $ md5sum debian-testing-i386-netinst.iso
    a20391b12f7ff22ef705cee4059c6b92  debian-testing-i386-netinst.iso
    

    Next, check that the md5sum of the burned disc matches as well. The following command should work. It uses the size of the image to read the correct number of bytes from the disc.

    $ dd if=/dev/cdrom | \
    > head -c `stat --format=%s debian-testing-i386-netinst.iso` | \
    > md5sum
    a20391b12f7ff22ef705cee4059c6b92  -
    262668+0 poster in
    262668+0 poster ut
    134486016 bytes (134 MB) kopierade, 97.474 sekunder, 1.4 MB/s
    

If, after the installer has been booted successfully, the disc is not detected, sometimes simply trying again may solve the problem. If you have more than one optical drive, try changing the disc to the other drive. If that does not work or if the disc is recognized but there are errors when reading from it, try the suggestions listed below. Some basic knowledge of Linux is required for this. To execute any of the commands, you should first switch to the second virtual console (VT2) and activate the shell there.

  • Växla till VT4 eller visa innehållet i /var/log/syslog (använd nano som redigerare) för att leta efter specifika felmeddelenden. Efter det, kontrollera även utskriften för dmesg.

  • Check in the output of dmesg if your optical drive was recognized. You should see something like (the lines do not necessarily have to be consecutive):

    ata1.00: ATAPI: MATSHITADVD-RAM UJ-822S, 1.61, max UDMA/33
    ata1.00: configured for UDMA/33
    scsi 0:0:0:0: CD-ROM            MATSHITA DVD-RAM UJ-822S  1.61 PQ: 0 ANSI: 5
    sr0: scsi3-mmc drive: 24x/24x writer dvd-ram cd/rw xa/form2 cdda tray
    cdrom: Uniform CD-ROM driver Revision: 3.20
    

    If you don't see something like that, chances are the controller your drive is connected to was not recognized or may be not supported at all. If you know what driver is needed for the controller, you can try loading it manually using modprobe.

  • Check that there is a device node for your optical drive under /dev/. In the example above, this would be /dev/sr0. There should also be a /dev/cdrom.

  • Use the mount command to check if the optical disc is already mounted; if not, try mounting it manually:

    $ mount /dev/hdc /cdrom
    

    Check if there are any error messages after that command.

  • Check if DMA is currently enabled:

    $ cd /proc/ide/hdc
    $ grep using_dma settings
    using_dma      1       0       1       rw
    

    A 1 in the first column after using_dma means it is enabled. If it is, try disabling it:

    $ echo -n "using_dma:0" >settings
    

    Make sure that you are in the directory for the device that corresponds to your optical drive.

  • If there are any problems during the installation, try checking the integrity of the installation media using the option near the bottom of the installer's main menu. This option can also be used as a general test if the disc can be read reliably.

5.4.2. Uppstartskonfiguration

Om du har problem med att kärnan hänger sig under uppstartsprocessen, inte känner igen kringutrustning som du faktiskt har, eller inte korrekt detekterar vissa enheter, är uppstartsparametrarna det första att kontrollera, vilket diskuteras i Avsnitt 5.3, ”Uppstartsparametrar”.

In some cases, malfunctions can be caused by missing device firmware (see Avsnitt 2.2, ”Enheter som kräver fast programvara” and Avsnitt 6.4, ”Läsa in saknad fast programvara”).

5.4.3. Software Speech Synthesis

If software speech synthesis does not work, there is most probably an issue with your sound board, usually because either the driver for it is not included in the installer, or because it has unusual mixer level names which are set to muted by default. You should thus submit a bug report which includes the output of the following commands, run on the same machine from a Linux system which is known to have sound working (e.g., a live CD).

  • dmesg

  • lspci

  • lsmod

  • amixer

5.4.4. Vanliga 64-bit PC Installationsproblem

Det finns några vanliga installationsproblem som kan lösas eller undvikas genom att skicka med vissa uppstartsparametrar till installationsprogrammet.

Om din skärm börjar visa en konstig bild vid uppstart av kärnan, exempelvis vitt, svart eller färgat bildpunktsskräp, kan ditt system innehålla ett problematiskt grafikkort som inte kan byta till framebuffer-läget korrekt. Då kan du använda uppstartsparametern fb=false för att inaktivera framebuffer-konsollen. Endast ett fåtal språk kommer då att finnas tillgängliga under installationen på grund av begränsade konsollfunktioner. Se Avsnitt 5.3, ”Uppstartsparametrar” för detaljer.

5.4.4.1. Systemet fryser under konfigurationsfasen för PCMCIA

Some very old laptop models produced by Dell are known to crash when PCMCIA device detection tries to access some hardware addresses. Other laptops may display similar problems. If you experience such a problem and you don't need PCMCIA support during the installation, you can disable PCMCIA using the hw-detect/start_pcmcia=false boot parameter. You can then configure PCMCIA after the installation is completed and exclude the resource range causing the problems.

Alternativt kan du starta upp installationsprogrammet i expertläget. Du kommer då att bli frågad att ange inställningar för resursintervall som din maskinvara behöver. Till exempel, om du har en av Dells bärbara datorer som nämndes ovan, bör du ange exclude port 0x800-0x8ff här. Det finns också en lista på några vanliga resursintervall i System resource settings section of the PCMCIA HOWTO. Observera att du måste ta bort eventuella kommatecken när du anger det här värdet i installationsprogrammet.

5.4.5. Tolkning av kärnans uppstartsmeddelanden

Under uppstartssekvensen kanske du se många meddelanden liknande can't find någonting , eller någonting not present, can't initialize någonting, eller till och med this driver release depends on någonting. De flesta av de här meddelandena är harmlösa. Du ser dem för att kärnan för installationssystemet är byggd för att köras på många olika datorer och med många olika kringutrustningsenheter. Ingen dator kommer så klart att innehålla alla tänkbara kringutrustningsenheter, så operativsystemet kan klaga en hel del när den letar efter kringutrustning som du inte har. Du kan också se att systemet gör en paus. Det händer när det väntar på att en enhet ska svara, och att den enheten finns inte i ditt system. Om du tycker att tiden det tar att starta upp systemet är på tok för lång, kan du skapa en anpassad kärna senare (se Avsnitt 8.5, ”Bygg en ny kärna”).

5.4.6. Rapportering av installationsproblem

If you get through the initial boot phase but cannot complete the install, the menu option Save debug logs may be helpful. It lets you store system error logs and configuration information from the installer on a storage medium, or download them using a web browser. This information may provide clues as to what went wrong and how to fix it. If you are submitting a bug report, you may want to attach this information to the bug report.

Andra relevanta installationsmeddelanden kan hittas i /var/log/ under installationen, och /var/log/installer/ efter datorn har startats om till det nyligen installerade systemet.

5.4.7. Skicka installationsrapporter

Om du fortfarande har problem, skicka in en installationsrapport. Vi uppmuntrar att installationsrapporter skickas in även om installationen lyckats, så att vi kan få så mycket information som möjligt om många olika maskinvarukonfigurationer.

Observera att din installationsrapport kommer att publiceras i Debians felhanteringssystem (BTS) och vidarebefordras till en publik sändlista. Se till att du använder en e-postadress som du inte har några problem med att den används publikt.

If you have a working Debian system, the easiest way to send an installation report is to install the installation-report and reportbug packages (apt install installation-report reportbug), configure reportbug as explained in Avsnitt 8.4.2, ”Skicka e-post utanför systemet”, and run the command reportbug installation-reports.

Alternatively you can use this template when filling out installation reports, and file the report as a bug report against the installation-reports pseudo package, by sending it to .

Package: installation-reports

Boot method: <How did you boot the installer? CD/DVD? USB stick? Network?>
Image version: <Full URL to image you downloaded is best>
Date: <Date and time of the install>

Machine: <Description of machine (eg, IBM Thinkpad R32)>
Processor:
Memory:
Partitions: <df -Tl will do; the raw partition table is preferred>

Output of lspci -knn (or lspci -nn):

Base System Installation Checklist:
[O] = OK, [E] = Error (please elaborate below), [ ] = didn't try it

Initial boot:           [ ]
Detect network card:    [ ]
Configure network:      [ ]
Detect media:           [ ]
Load installer modules: [ ]
Detect hard drives:     [ ]
Partition hard drives:  [ ]
Install base system:    [ ]
Clock/timezone setup:   [ ]
User/password setup:    [ ]
Install tasks:          [ ]
Install boot loader:    [ ]
Overall install:        [ ]

Comments/Problems:

<Description of the install, in prose, and any thoughts, comments
      and ideas you had during the initial install.>

In the bug report, describe what the problem is, including the last visible kernel messages in the event of a kernel hang. Describe the steps that you did which brought the system into the problem state.