Re: Fedora 30 and problem with monitor resolution detection in gdm/Gnome?
On 12 May 2019, at 23:47, Tom Horsley <horsley1953(a)gmail.com>
wrote:
I have similar problems with using my LG OLEDB6P 4K TV as a
monitor. The nouveau driver seems to be confused by the
EDID information. Using X it picks some resolution the
monitor can't even display (invalid signal on monitor),
using wayland I thought it worked, but when I examined
the details it picked a strange resolution that the monitor
could display, but wasn't the native 3840x2160.
When I switched to the nvidia binaries from rpmfusion
it sees 3840x2160 in EDID as the best resolution and
displays it no problem.
I have this feeling someone has been "improving" the
EDID detection in the open source video drivers.
https://bugzilla.redhat.com/show_bug.cgi?id=1648608
https://bugzilla.redhat.com/show_bug.cgi?id=1575391
I think this started back in fedora 28, but I only
recently dug into it in more detail and added info to
that first bugzilla.
There are a number of ways that I have seen EDID problems.
The most popular issue the monitor's EDID is wrong.
I think there are quirks tables in the kernel to fix up the well know
issues (but it'd been a long time since I had to know about this
stuff for work).
It used to be that you would see error reports in dmesg
if the I2C bus has problems.
You can look at the details with:
$ xrandr --verboes | edid-decode
The "Detailed timing" are the monitors prefered mode I recall.
Barry