Comme=
nt # 11
on bug 10619=
1
from Fran=C3=A7ois Jacques
The bug is caused by having both the audio signal and image simultaneously,=
it
seems.=20
After I added "radeon.audio=3D0" to the kernel argument list and =
rebooted, the
video interface and the monitor concluded their signal handshake successful=
ly
(!) and I could switch the monitor to full res and, lo' behol', a 1440p im=
age
(!!).
For future reference, should anyone have issues, try radeon.audio=3D0. If y=
ou
were relying on the radeon for audio, look for an alternative, or use a
DP-to-HDMI adapter and tolerate the lower resolution until the bug is fixed.
----
Googling on this specific symptom revealed multiple regressions on this mat=
ter
before, it could be a new one or it's been lurking for a while. Which means
either:
- tons of dupes in the DRM bugs list wrt radeon and DP /w audio enabled and
users don't know how to disable it.
- all radeon users having switched their audio off
- most radeon users gave up on their DisplayPort or their radeon-based card
altogether (perhaps switching brand in the process, frustration kicking in)
- it's a recent regression and I've been lucky to catch it before the kernel
goes mainstream in major distros.
I'll still provide a dmesg dump, this time with drm.debug=3D0x06 (0x06 any =
good?
any prefered value?) by rebooting with audio back on and image gone.