[ltp] E575 screen freezing (was:) Re: Dual-boot with Windows 10

[cr]

On Sun, 25 Apr 2021 21:13:24 +0300
Marius Gedminas <marius at gedmin.as> wrote:

> On Sun, Apr 25, 2021 at 08:54:40PM +1200, cr wrote:
> > Okay, update:   I decided it was getting too messy to leave Windows
> > in place, if I need it in future I'll try the VM method.    (I do
> > have a L440 which is dual-boot, but Win10 seems to want to mess
> > with the boot order any time I run it).
> 
> FWIW that's not the case on my X390.  Win 10 + Ubuntu dual-boot,
> friendly-like.

I have several older Thinkpads (T400, T520) where Windows (XP or 7)
works quite happily dual-boot with Debian or Mint.   But Win 10 seems
to have a habit of trying to modify the boot sequence.   

> > This all works *except* there's a problem with the screen and
> > keyboard/mouse freezing after a while, I suspect because I'm
> > getting an error 'Firmware bug:  IOAPIC not in IVRS table'   which
> > is related to IOMMU.   There's no way to disable IOMMU in the BIOS
> > settings so I may just have to do it in Grub.   But I don't think
> > that has any relation to BIOS vs UEFI.
> 
> Arent IOAPIC and IOMMU rather different things?

Um, the web pages that mention IOAPIC also sometimes suggest disabling
IOMMU.    But I'm still checking with that.   
The reason I suspect IOAPIC is the boot messages that say:

[Firmware bug]: AMD-Vi: IOAPIC[4] not in IVRS table
[Firmware bug]: AMD-Vi: IOAPIC[5] not in IVRS table
No Southbridge IOAPIC found
AMD-Vi: disabling interrupt mapping
mmc0: Unknown controller version (3). You may experience problems.

(Although it was that last line that made me sit up and take notice,
mmc0 is the SD card controller so probably not related to current
issues)

> When mouse/keyboard freeze, is the system otherwise alive?  E.g. do
> things change on screen (blinking cursors, seconds in a clock, values
> shown by top)?  Does it respond to network packets?  Can you ssh in?
> 
> How deeply is the keyboard frozen?  Any reaction to Caps Lock?
> Ctrl+Alt+F3?  Alt+SysRq+S,U,B?  Would an external USB keyboard work if
> plugged in? 

> Is the freeze temporary or permanent?

When Debian (10.9.0 AMD64) first boots up, everything works.   But if I
go to run e.g. Synaptic, it draws the first window and then freezes,
with it part-drawn. The mouse pointer moves but nothing else works,
keyboard, mouseclicks, nothing.   As if it's jammed up.   
Capslock toggles its light.   No key combinations have any effect.
I don't think it's a keyboard issue though.   Only escape is the power
button.

I have ssh'd in.   And that keeps working even when the E575's screen
is jammed.   So wifi is still working.  Very handy as I can view
lspci, /var/log etc.

Yet, if I first launch LibreOffice Writer instead, which I assume is a
memory-hungry app, it works fine, at least for a while.   If I launch a
terminal window I can carry on inside it for ages.   So it seems to be
something in the window manager that's getting stuck.  

(Now, something must have timed out, as the screen started to fade,
moving the mouse brought it back and the Task Manager window popped
up.   Showing CPU usage 12%, memory 396MB of 7441 MB used.   All
tasks showing 0% CPU%.   But I still can't scroll it, move it or do
anything else with it.)

(Must run memtest but I doubt it's RAM-related, that would be too easy)

I updated the BIOS (first time I ever flashed a BIOS.   Lenovo provide
a Windows updater but also, to their credit, a bootable ISO.  I
couldn't get it to boot off USB - probably something I did worng making
the USB stick - but it did boot off a CD).   But no change to the
problem.

There are a number of web pages on disabling IOMMU / remapping IOAPIC
in Grub, which is what I'll try next.

Chris