On Tue, 18 Jan 2022 14:55:11 -0000
"Rogan Dawes" <fedora(a)rogan.dawes.za.net> wrote:
I have a 43" Samsung Smart TV that I am using as a monitor with
a
ThinkPad P51, running Fedora 35 Workstation Edition. This laptop has
a "NVIDIA Corporation GM206GLM [Quadro M2200 Mobile] / Mesa IntelĀ® HD
Graphics 630 (KBL GT2)" graphics subsystem. As far as I can make out,
I am using the latest NVidia driver (495.46).
What is unfortunately happening, is that if my laptop goes to sleep,
the TV sees that the source disappears, and "tries to look for the
laptop", repeatedly. This ends up waking up the laptop (sometimes),
until the TV eventually gives up and turns itself off. The problem is
then that the laptop no longer detects that the TV is connected to
the HDMI port, and I have to reboot to allow the laptop to detect the
screen again. Xrandr does not detect the display if run manually, and
the Settings app Displays page also doesn't show the TV.
When you say 'turns itself off', does it actually fully power down?
Have you tried powering down the TV, waiting 10 or 15 seconds, and then
powering back up? It should look for a source again, and if the laptop
is not sleeping, it should find it, and everything should just work.
Another thought. Have you tried reloading the video driver when you
take the laptop out of sleep? It should look for outputs, and if the
TV is only in suspend, it might respond to status queries. Seems
doubtful, because if the laptop was aware there was a connection when
it went to sleep, it probably tries sending output to the TV when it
wakes. And that isn't waking the TV.
This is a rather difficult thing to google, I have had zero results
in my searching.
I also tried looking for any logs that would indicate what went
wrong, but I found nothing in the syslog, etc.
I don't think anything went wrong. There is just a procedural mismatch
between the TV and the laptop. Once the TV turns itself off because
there is no input, it seems to be unavailable for being turned on.
What is the startup sequence like? Do you start the laptop and then
turn the TV on? Or could it be that they are turned on simultaneously,
and the TV is still looking for a source when the laptop finishes
booting, and thus finds one?
Can anyone give me pointers on how I can start debugging this? I am
fairly technical, so can certainly follow instructions. I'm guessing
I need to enable verbose logging for the driver so it can report when
new displays are connected or disconnected, as well as any actions
around those events?
No experience whatsoever with this, but that sounds reasonable. From
the symptoms though, I don't think this is a driver issue. I think the
TV is set up to ignore attempts to connect once it doesn't find a
source, and that it only looks for sources at power up.