Mailing List Archive

Screen blanking issue with NVidia 455 drivers
Not sure if this is the best place for this, but I am having an issue with
MythTV 0.31 and the latest NVidia drivers. My system is ArchLinux and the
latest NVidia drivers are 455.23.04.

What I'm experiencing is that when I pause anything (live tv or videos) for
a long enough time, the output to the TV goes to sleep to the point that
the only way I can get it back is to use CTRL+ALT+F2 to switch to a virtual
tty, then CTRL+ALT+F1 to get back to the X display. This also is the case
if I turn my TV off and then immediately back on.

I haven't touched my Xorg config in about 6 months, and things were working
fine until recently. I tried rolling back my NVidia drivers to version
450.66 (left Xorg config alone), rebooted and tested again and it works
fine, the problem goes away.

Again, not sure if this mailing list is the appropriate place to raise
this, but I thought it might help anyone that happened to have the same
issue. For now I'll stick with the slightly older drivers and maybe check
the NVidia forums to see if it's a known issue.

Thanks,
Erik
Re: Screen blanking issue with NVidia 455 drivers [ In reply to ]
On Wed, 23 Sep 2020 13:26:46 -0500, you wrote:

>Not sure if this is the best place for this, but I am having an issue with
>MythTV 0.31 and the latest NVidia drivers. My system is ArchLinux and the
>latest NVidia drivers are 455.23.04.
>
>What I'm experiencing is that when I pause anything (live tv or videos) for
>a long enough time, the output to the TV goes to sleep to the point that
>the only way I can get it back is to use CTRL+ALT+F2 to switch to a virtual
>tty, then CTRL+ALT+F1 to get back to the X display. This also is the case
>if I turn my TV off and then immediately back on.
>
>I haven't touched my Xorg config in about 6 months, and things were working
>fine until recently. I tried rolling back my NVidia drivers to version
>450.66 (left Xorg config alone), rebooted and tested again and it works
>fine, the problem goes away.
>
>Again, not sure if this mailing list is the appropriate place to raise
>this, but I thought it might help anyone that happened to have the same
>issue. For now I'll stick with the slightly older drivers and maybe check
>the NVidia forums to see if it's a known issue.
>
>Thanks,
>Erik

Did you try just using the shift key on the keyboard, or using the IR
remote blindly to cause a screen change? If what you are seeing is
DPMS blanking, either of those would cause the screen to display
again. Using Ctrl-Alt-F2 also works, but is more than is needed. I
have off and on again problems with recent Nvidia drivers and DPMS.
Even when I have:

Option "DPMS" "false"

in the Monitor section of my /etc/xorf/conf file, the drivers
sometimes disobey this and enable DPMS anyway. When this happens, I
have to change the DPMS option to "true" and tell DPMS that all of its
timeouts that cause it to blank the screen are disabled:

Section "ServerFlags"
Option "BlankTime" "0"
Option "StandbyTime" "0"
Option "SuspendTime" "0"
Option "OffTime" "0"
EndSection

That normally fixes this problem.

I have had this same problem in the past with much older Nvidia
drivers, so I have always suspected that it is triggered by some of
the other configuration I am putting in my xorg.conf file. Just last
night I made a change to my xorg.conf file and had the problem come
back again using the 450.66 drivers. So today I am going to have to
turn on the workaround again and reboot, when I have a gap in the
recordings.
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Re: Screen blanking issue with NVidia 455 drivers [ In reply to ]
I did try pressing remote buttons and keys on the keyboard to try to wake
it up, but the screen stays blank. In fact, the TV shows what it would show
for a disconnected input. I am not 100% certain, but while I was having the
problem, with the screen blank, I could press a button on my remote to
start playing Live TV. I wouldn't see or hear anything on the TV. But if I
used the keyboard to CTRL+ALT+F2 out to TTY2, then press CTRL+ALT+F1 to go
back to X, I could see whatever channel it started playing on and hear the
audio. The playback is jumpy when I do this, but stopping playback and
restarting works fine and the system is ok until the next time I turn the
TV off or stop playing content.

I did see your suggestion about the Xorg config for DPMS on another thread.
I didn't have those settings in my config, but I tried them to see and it
made no difference. On my system, I have mythfrontend started with a small
script that uses "xset" to disable the screensaver and disable DPMS:

xset s off -dpms && mythfrontend

This has worked for me for a few years now to keep the system screensaver
from kicking in and from DPMS blanking the screen for power savings. My
Xorg.conf is pretty small, and like I said, it hasn't changed for a number
of NVidia driver and kernel upgrades.

I looked briefly on the NVidia forums to see if anyone else was having a
similar issue, but didn't really find anything. At this point, I'm content
with leaving my NVidia drivers on 450.66 as it just works with those
drivers. The 455.23.04 drivers are technically beta drivers, but they are
the ones ArchLinux has as current. So for now, I'll just pin/hold back
upgrades on my NVidia drivers. I'll keep checking as NVidia and ArchLinux
update drivers and see if the problem is resolved down the road, but I have
a work-around for now.

With the limited investigation I've done so far, I'd say this is an issue
with the NVidia drivers, and not likely an issue in MythTV.

Many thanks,
Erik

On Wed, Sep 23, 2020 at 10:12 PM Stephen Worthington <
stephen_agent@jsw.gen.nz> wrote:

> On Wed, 23 Sep 2020 13:26:46 -0500, you wrote:
>
> >Not sure if this is the best place for this, but I am having an issue with
> >MythTV 0.31 and the latest NVidia drivers. My system is ArchLinux and the
> >latest NVidia drivers are 455.23.04.
> >
> >What I'm experiencing is that when I pause anything (live tv or videos)
> for
> >a long enough time, the output to the TV goes to sleep to the point that
> >the only way I can get it back is to use CTRL+ALT+F2 to switch to a
> virtual
> >tty, then CTRL+ALT+F1 to get back to the X display. This also is the case
> >if I turn my TV off and then immediately back on.
> >
> >I haven't touched my Xorg config in about 6 months, and things were
> working
> >fine until recently. I tried rolling back my NVidia drivers to version
> >450.66 (left Xorg config alone), rebooted and tested again and it works
> >fine, the problem goes away.
> >
> >Again, not sure if this mailing list is the appropriate place to raise
> >this, but I thought it might help anyone that happened to have the same
> >issue. For now I'll stick with the slightly older drivers and maybe check
> >the NVidia forums to see if it's a known issue.
> >
> >Thanks,
> >Erik
>
> Did you try just using the shift key on the keyboard, or using the IR
> remote blindly to cause a screen change? If what you are seeing is
> DPMS blanking, either of those would cause the screen to display
> again. Using Ctrl-Alt-F2 also works, but is more than is needed. I
> have off and on again problems with recent Nvidia drivers and DPMS.
> Even when I have:
>
> Option "DPMS" "false"
>
> in the Monitor section of my /etc/xorf/conf file, the drivers
> sometimes disobey this and enable DPMS anyway. When this happens, I
> have to change the DPMS option to "true" and tell DPMS that all of its
> timeouts that cause it to blank the screen are disabled:
>
> Section "ServerFlags"
> Option "BlankTime" "0"
> Option "StandbyTime" "0"
> Option "SuspendTime" "0"
> Option "OffTime" "0"
> EndSection
>
> That normally fixes this problem.
>
> I have had this same problem in the past with much older Nvidia
> drivers, so I have always suspected that it is triggered by some of
> the other configuration I am putting in my xorg.conf file. Just last
> night I made a change to my xorg.conf file and had the problem come
> back again using the 450.66 drivers. So today I am going to have to
> turn on the workaround again and reboot, when I have a gap in the
> recordings.
> _______________________________________________
> mythtv-users mailing list
> mythtv-users@mythtv.org
> http://lists.mythtv.org/mailman/listinfo/mythtv-users
> http://wiki.mythtv.org/Mailing_List_etiquette
> MythTV Forums: https://forum.mythtv.org
>
Re: Screen blanking issue with NVidia 455 drivers [ In reply to ]
On Thu, 24 Sep 2020 08:44:06 -0500, you wrote:

>I did try pressing remote buttons and keys on the keyboard to try to wake
>it up, but the screen stays blank. In fact, the TV shows what it would show
>for a disconnected input. I am not 100% certain, but while I was having the
>problem, with the screen blank, I could press a button on my remote to
>start playing Live TV. I wouldn't see or hear anything on the TV. But if I
>used the keyboard to CTRL+ALT+F2 out to TTY2, then press CTRL+ALT+F1 to go
>back to X, I could see whatever channel it started playing on and hear the
>audio. The playback is jumpy when I do this, but stopping playback and
>restarting works fine and the system is ok until the next time I turn the
>TV off or stop playing content.
>
>I did see your suggestion about the Xorg config for DPMS on another thread.
>I didn't have those settings in my config, but I tried them to see and it
>made no difference. On my system, I have mythfrontend started with a small
>script that uses "xset" to disable the screensaver and disable DPMS:
>
>xset s off -dpms && mythfrontend
>
>This has worked for me for a few years now to keep the system screensaver
>from kicking in and from DPMS blanking the screen for power savings. My
>Xorg.conf is pretty small, and like I said, it hasn't changed for a number
>of NVidia driver and kernel upgrades.
>
>I looked briefly on the NVidia forums to see if anyone else was having a
>similar issue, but didn't really find anything. At this point, I'm content
>with leaving my NVidia drivers on 450.66 as it just works with those
>drivers. The 455.23.04 drivers are technically beta drivers, but they are
>the ones ArchLinux has as current. So for now, I'll just pin/hold back
>upgrades on my NVidia drivers. I'll keep checking as NVidia and ArchLinux
>update drivers and see if the problem is resolved down the road, but I have
>a work-around for now.
>
>With the limited investigation I've done so far, I'd say this is an issue
>with the NVidia drivers, and not likely an issue in MythTV.
>
>Many thanks,
>Erik

From your description, the blank screen seems likely to be one done by
the TV because it is seeing a clock rate that is too high. Just why
switching to Ctrl-Alt-F2 and back again fixes that is unknown but it
certainly sounds like an Nvidia driver bug. I have had ones like that
before. The reason for the jumpy playback after going back to
Ctrl-Alt-F1 is likely that mythfrontend does not know the screen mode
has changed to one the TV can cope with and it is playing back at a
different frame rate than the screen is displaying things at. When
you restart playback, mythfrontend will be querying the screen to find
out the frame rate or setting it to the frame rate it wants and with
everything matching, playback is smooth.
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