On Friday, 23 August 2024 17:21:42 BST Alan Mackenzie wrote: > Hello, Michael. > > On Thu, Aug 22, 2024 at 22:44:47 +0100, Michael wrote:
> > 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. I am not sure a modern BIOS would get stuck as you're describing. I think the MoBo will detect any graphics chips connected to it, in this case your integrated APU graphics chip, and the graphics chip will in turn prompt for any connected display hardware. In this case your monitor should respond and send the EDID data to the graphics chip, which will adjust its signal to what the monitor requires. > > .... 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 normally power off peripherals, except for USB devices, before I disconnect/ reconnect cables. Especially legacy IRQ connected kit which is not hot- swappable - e.g. PS/2 connectors. Modern systems don't have such issues, but I'm used to taking this precaution. :-p > 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. 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. Do you still get this offset problem if you remove the KVM switch and connect the monitor directly to the MoBo? 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. > 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.
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