Dear Maintainer,

Upon loading, sddm displays black screen with no cursor. It is still possible
to login. Once logged in sddm brings up the KDE desktop normally.

This occurs only over hdmi with nvidia-driver (current). When switching to a
vga cable problem disappears. Also, this problem does NOT occur with
nvidia-legacy-340xx-driver regardless of connection type.

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This bug, previously reported by me, still exists in sddm 0.15.0-1

Additional information:

The problem (black/blank screen) exhibits only when connected via an A/V
receiver.  Sddm displays normally when attached directly to the TV (4k).

NVidia softare correctly enumerates the A/V device, so the latter must be
sending correct EDID info. Also, it reports 1080p resolution, which is the
maximum input resolution for the A/V device.

The problem clearly lies with sddm. BIOS displays correctly, grub boot menu
displays correctly, and the KDE desktop displays correctly. Only sddm fails to
display correctly, though it did display correctly when previously using a
legacy NVidia device on the same system.

Why? There is no full evidence of that.

SDDM might be using something the nVidia card does not supports, that
wouldn't be the first time it happens I'm afraid. The fact that you
see this only with SDDM doesn't means it's SDDM's fault.

Now if you could reproduce the bug with another video card, specially
with open drivers, that would be another story (or not).

OK. It's not absolutely certain the problem lies ONLY with SDDM. But
since BIOS, Grub and KDE have no problem with Nvidia, it certainly does
seem LIKELY the problem is with SDDM. It's not like there hasn't been a
long history of issues with SDDM.