Hello again, Michael. On Sat, Aug 24, 2024 at 16:40:38 +0100, Michael wrote: > On Saturday, 24 August 2024 14:25:31 BST Alan Mackenzie wrote: > > On Sat, Aug 24, 2024 at 10:44:44 +0100, Michael wrote:
> > > Instead of resetting the firmware and losing all your MoBo settings, you'd > > > be better off to flash the latest firmware on the MoBo. UEFI MoBo > > > firmware usually offers the option to back up your settings first. MSI > > > support would probably ask you to do this and reset all settings anyway, > > > before they deal with any issues. > > I think you're right, there. Unless I've already got the latest firmware > > installed (the form to fill in for MSI asked for the firmware version, > > which I gave). > > > Do you still get this offset problem if you remove the KVM switch and > > > connect the monitor directly to the MoBo? > > I tried that, but got no display signal at all. Maybe I had the wrong > > cable plugged into the wrong socket, but I don't think so. There's a > > veritable rats' nest of cables behind my PCs which is moderately > > difficult to get to. I was able to shut the machine down by logging in > > as root blind, and typing shutdown -h now, so the machine defintely came > > up. > Hmm ... normally you would have a display coming up, if your PC is indeed > connected to the monitor. This would be the first thing I would try to make > sure I can get a correct display. :-/ I also tried (a day or two ago) sticking the HDMI->DVI adapter into my current PC's graphic card's HDMI slot. I also got no signal this way. (My current PC has a graphic card with both DVI and HDMI slots on it.) Maybe there's something very close to tolerance somewhere, somehow, that my HDMI->DVI adapter is somehow pushing out of tolerance. Or something like that. > > With the new PC connected up through the KVM switch (and also an > > HDMI->DVI adapter) I'm still getting the 5cm. gap at the LH side of the > > screen. I've installed X and xfce, and that displays poorly, with lots > > of flickering, shimmering colour threads through the display. I suspect > > my HDMI->DVI adapter may be broken. The display goes blank for several > > seconds then comes back again several times a minute. I saw something > > like this when I booted KDE from the live-CD a few days ago to see the > > firmware files needed. > This reads like an unsuitable refresh rate problem. I've read the "information" section from my monitor's adjustment panel. It says 60 Hz. and 1920x1080 (on my current machine). On the new machine, it reads 60 Hz., 2112x1016. This looks like being at the core of the problem. 2112 / 1920 = 1.1 (more or less), i.e. 10% too many pixels. My monitor is ~52cm wide. 10% of this is the ~5cm. black strip at the LHS of the monitor. Is there any convenient way I can display the current EDID information block? > > It's worth noting that my display was also imperfect when I plugged > > laptops into it a couple of years back, but not so bad as my xfce is now. > > > What may be happening is the KVM causes some distortion to the signal > > > amplitude/frequency, which the monitor interprets as an offset. You could > > > try to tweak this by feeding a bespoke EDID to the kernel, but sometimes > > > a simple cable swap or operating the KVM a few times can cure it. > > Maybe, but it's all digital, not analog, isn't it? I remember tweaking > > timings in .xinit for CRT monitors (a tedious job, indeed), but surely an > > EDID signal is either going to be read by the OS correctly, or not at > > all? > Yes, the processing is digital, but the noise on the wire may not be. I've > seen an LED monitor randomly coming up with a lot of distortion on console or > DM (SDDM), everything flickering and double image/shading, only for the > display to reset perfectly when a Plasma desktop is launched, or after the PC > is rebooted. If the handshake between the card and the monitor is incorrect > when hardware is initialised, then you'll need a reset of sorts to start > again > with the correct EDID parameters. I've tried to reset the monitor via its adjustment panel, but I don't think I managed the final step. In any case, the monitor just carried on as before. > > I've already tried swapping the cables to the KVM box, this achieving > > nothing. > > > > 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. > > > Well, we don't know if this is caused by a MoBo firmware bug, although the > > > quality of firmware often leaves much to be desired. > > We don't know, no, so I have to guess so as to come up with tests to try. > > ;-) The firmware on this MB fails to save the boot order when I put the > > DVD drive at the start, in front of the NVMEs (which are still called > > "hard drives"). Thus the BIOS isn't perfect. > > I'm still pretty sure that when I booted the machine for the first time, > > the display was correct. In particular, I remember noticing the offset > > after I tried booting with the drm.edid_firmware kernel parameter for the > > first time. > I expect, but don't know, the embedded kernel drm.edid_firmware codes offer > some default resolution sizes and refresh rates. If your monitor prefers > e.g. > 59Hz as opposed to a default of 60Hz, you could experience the problems you > describe above. I was thinking if you can get a correct display coming up > with the monitor connected directly to the graphics port, then you can > capture > the EDID reported by the monitor and feed this to the kernel as an EDID file > instead. That's not possible at the moment as the monitor is only DVI (or VGA), and the new machine is HDMI or DisplayPort. > > I think I should try to update the firmware, and see if that clears the > > problem. > The latest firmware is 7D75v1J and was released very recently. It deals with > a security issue too, so it's advisable using this version sooner or later: > https://www.msi.com/Motherboard/MAG-B650-TOMAHAWK-WIFI/support Yes, I "updated" the firmware, even though it was already on that latest version. It didn't help. > Besides trying the latest firmware, some other things to try: > 1. Use a cable with the appropriate connectors at each end. No KVM, no > intermediate adaptors, no extensions, nothing-in-between. Then add one thing > at a time to see what makes a difference. Not something I have at the moment, but I could try to get one next week. > 2. Try reseting the monitor itself. Usually there is some OSD menu to adjust > monitor settings, see if there is a 'Reset Display' or similar option. I found this, but couldn't work out how to press the final GO button. > 3. Check if the monitor display corrects itself by playing with refresh rates > using xrandr/xorg.conf/desktop GUI Display settings after you launch xfce. I'll need to look into this. > 4. You should not have to do this, but if the KVM consistently throws out the > offset then check if the monitor OSD has a screen adjustment submenu to tweak > the screen viewport and shift it to fit the monitor. My hypothesis at the moment is that something in the new machine is wrongly pumping out 2112x1016 in place of 1980x1080 and this is diminishing the size of (and reducing the quality of) the displayed image. I think the EDID being received from the monitor and KVM-box are correct, but that the BIOS is applying some "correction" to them, for some reason. Maybe I should try resetting the CMOS ram. > Let's hope one of these things delivers a working display for you. :-) Thanks! -- Alan Mackenzie (Nuremberg, Germany).
