Re: [gentoo-user] New machine: Contents of display are offset around 2 inches from the left hand side.

[Alan Mackenzie <acm@muc.de>]

Hello, Michael.

On Thu, Aug 22, 2024 at 22:44:47 +0100, Michael wrote:
> On Thursday, 22 August 2024 17:54:19 BST Alan Mackenzie wrote:
> > Hello, Gentoo.

> > Thanks to everybody who helped me get my video going in the other thread.

> > I've now got a more puzzling problem:  Every time I boot up my new
> > machine, the 1920x1080 pixel display is offset by around 2 inches from
> > the left hand side (and aroun 1 cm from the top).  It still appears to be
> > 1920x1080 pixels (more precisely, 240 columns x 67 lines of 16x8
> > characters), but it's not filling the screen.

> > The screen itself is attached to a KVM box, and it works just fine on the
> > old machine.  So it's not the physical display which is at fault.  It's
> > an around 10 year old Samsung digital monitor, not some ancient CRT, or
> > anything like that.  It's interface is a DVI cable.

> > I seem to remember it filled the screen when it was new (on Monday).

> > Part of my efforts to make the video work (see other thread) involved
> > giving the kernel the drm.edid_firmware parameter.  This parameter is
> > intended to compensate for the display/KVM box/whatever failing to supply
> > the correct EDID information to the PC.  One of the settings I tried
> > involved the offsets from the left and top mentioned above.  But somehow
> > they seem to have got stuck in the machine.  It seems the BIOS has saved
> > the offsets in the CMOS or something.  I don't know how to undo these
> > saved settings.

> > Would somebody please help me on this, too.

> > Thanks!

> I must have missed the other thread where you had to feed to the kernel an  
> drm.edid_firmware file.

Sorry, I phrased that badly.  As part of the other problem I tried using
drm.edid_firmware, but I didn't mention it in that thread.

> Assuming the file is still available and built in the kernel as
> firmware, ....

I used one of the stock options, drm.edid_firmware=edid/1920x1080.bin.
There's something in the kernel that recognises these 6 or 7 "file names"
and uses the built in EDID blocks for them rather than reading from
/lib/firmware.

But the source code for these has things like XOFFSET parameters, so I'm
thinking that one of these took effect and "got stuck", somehow.

> .... then the problem could well have to do with the DVI cable.  It may
> be worth unplugging and replugging it.

I tried pulling the cable (whilst switched on) and replacing it.  This
didn't help (but doesn't seem to have done any damage, either ;-).

I haven't tried anything desperate, like clearing the CMOS, yet.

I've sent a support request to the manufacturers, MSI, which they will
hopefully answer some time next week.  In the mean time, I'll just have
to carry on intalling/configuring Gentoo with a nasty black stripe on my
screen.

I'm a bit fed up with all of this.  It's a new machine, but the
motherboard, an MSI B650 Tomahawk Wifi, has been around a fair while and
bugs in its BIOS ought to have been fixed by now.

-- 
Alan Mackenzie (Nuremberg, Germany).