XPost: uk.comp.os.linux   
   From: java@evij.com.invalid   
      
   I still have an old PC dual-booting (X)Ubunutu 22 & flavours of Windows.   
     Currently, it triple boots via GRUB between Ubuntu 22, Windows XP   
   32-bit, & Windows 10, where the OS partitions are all primaries, while   
   the two data partitions are logical drives in an extended partition:   
      
   Win 10 Pro | Win XP-32 | Ubuntu 22 Root || Win Data | Ubuntu 22 Home ||   
      
   However, now I wish to add another bootable partition, so, instead of   
   booting from a new volume in the extended partition by shuffling the   
   existing partitions around to make room for it, I've decided to reformat   
   the entire disk as GPT/BIOS.   
      
   Accordingly, as a proof of concept and to act as a working Linux system   
   to boot from while accomplishing this, and to preserve the Windows Data   
   partition which holds all the necessary Windows images for repopulating   
   the original disk, I've formatted a spare disk in an external USB dock   
   as follows ...   
      
   Boot | Win7 | Win 10 | Win 32-bit | Ub 22 Root | Win Data | Ub 22 Home |   
      
   ... have copied the two Ubuntu partitions and the Windows Data   
   partition, have successfully installed GRUB, which found not just the   
   Ubuntu on the external disk but also the still existing options on the   
   internal hard disk and can boot into either Ubuntu.  However, while   
   Ubuntu on the internal HD still boots normally even though GRUB is now   
   on the external disk, with the Ubuntu on the latter there is a problem   
   in that the GUI won't start, and messages concerning trying to start it   
   disrupt anything that you try to type into the  text console by   
   constantly switching you back to the primary console, and when you   
   switch back to the one you're trying to type into, you have just a   
   couple of seconds or so to type something in before being switched away   
   again.   
      
   The messages are, where nn is an number incrementing by 1 on each   
   occurrence (beware possible unintended line wrap) ...   
      
   Starting Light Display Manager...   
   Started Light Display Manager.   
   Started session Cnn of User lightdm [ OK ] Stopped Light Display Manager.   
   Starting Detect the available GPUs and deal with any system changes...   
   [ 1296.065219*] nouveau 0000:01:00.0 fb: trapped read at 01004b0034 on   
   channel -1 [0fee0000 unknown]  engine 06 [BAR] client 08 [PFIFO_READ]   
   subclient 01 [IN] reascon 00000002 [PAGE_NOT_PRESENT]   
   Finished Detect the available GPUs and deal with any system changes.   
   [Repeat ad nauseam]   
      
   * this number also increments, I presume it's a time since boot up or   
   something like that.   
      
   ... which I have reduced to just the nouveau messages by typing ...   
      
        systemctl stop gpu-manager.service   
      
   ... interspersed with ...   
      
   Starting CUPS scheduler.   
   Stopped CUPS scheduler.   
   Stopping CUPS scheduler...   
   Starting CUPS scheduler.   
   [FAILED] Failed to start CUPS scheduler.   
   See 'systemctl status cups.service' for details   
      
   ... though I think I've managed to stop these latter by typing ...   
      
        systemctl stop cups.service   
      
   I'm guessing that Ubuntu is trying to find a display chip in the   
   hardware of the dock, which of course is bound to fail, and to fix it I   
   will have temporarily to swap the disks around, which is what I will try   
   next, but can anyone explain exactly what is going wrong, and suggest   
   how to make it work?  For example, how does a suck-it-and-see Linux   
   distro USB stick avoid this situation?   
      
   --   
      
   Fake news kills!   
      
   I may be contacted via the contact address given on my website:   
   www.macfh.co.uk   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)