[SOLVED] rtc timing on ubuntu based systems?

[tonyguadagno]

hi, i am running mythtv .27fixes on ubuntu 14.05 with an nvidia 730 and drivers 375.66. I am trying to get the most out of my frontend. I have been reading up on timing and it seems that myth does not support vblank on nvidia cards. I am also under the impression that rtc timing is better than usleep (not sure if that is true?) so i am trying to set up my frontend for rtc timing. there is a wiki out there
https://www.mythtv.org/wiki/Frame_displ ... _Frequency
that is out of date that says basically .... add a udev rule to set /dev/rtc(0) to 0664 and then echo 1024 to /sys/class/rtc/rtc0/max_user_freq . The problem is that on modern ubuntu systems, when i do the echo (even sudo) i get this:

Code: Select all

tonyg@MythHomeFE1:~$ sudo echo 1024 > /sys/class/rtc/rtc0/max_user_freq
-bash: /sys/class/rtc/rtc0/max_user_freq: Permission denied

Code: Select all

tonyg@MythHomeFE1:~$ ls -la /dev/rtc*
lrwxrwxrwx 1 root root      4 Jul 28 11:21 /dev/rtc -> rtc0
crw-rw-rw- 1 root root 251, 0 Jul 28 11:21 /dev/rtc0

so here are my questions
1. will myth ever support vblank on nvidia cards?
2. is it possible to use rtc timing with modern ubuntu systems

[tonyguadagno]

while i never heard from anyone about nvidia's (or myths) support for vblank, i did finally figure out how to enable rtc. I have put my finding on the timing wiki under the section "systemd method" https://www.mythtv.org/wiki/Frame_displ ... emd_method

hope this helps.

[bill6502]

Hi,

When using sudo, redirection doesn't work as one might expect. This is
the solution: echo "stuff" | sudo tee /somewhere/else

The new Wiki entry is a good solution, thanks. The existing Wiki does
mention sudo and that's been modified.

[tonyguadagno]

Bill, thanks, btw, do you know anything about vblank and whether or not it is myth that does not support it of nvidia?

thanks

[bill6502]

Sorry, I don't know. You can look in your mythfrontend.log to see if
there are any hints (I can see that there are some log messages
generated regarding VBLANK.)

[tonyguadagno]

bill, not many hints there, this is the message, but i have heard rumors that it is really myth that does not support vblank, do you know where i could go to find out more?

thanks

Aug 4 21:24:47 MythHomeFE1 mythfrontend.real: mythfrontend[8214]: E CoreContext vsync.cpp:277 (TryInit) VSYNC: DRMVideoSync: VBlank ioctl did not work, unimplemented in this driver?

[bill6502]

You might find discussions on the MythTV mailing list. Here's a link to the
archive: https://lists.gt.net/engine?list=mythtv ... ing=vblank