[mythtv-users] NVCtrl: The NV-CONTROL X extension is not available on screen 0 of ''

[John Pilkington]

On 02/12/2019 20:51, John Pilkington wrote:
> On 29/11/2019 23:59, John Pilkington wrote:
>> I'm getting that 'Info' message on startup of mythfrontend, 
>> 2019-render branch, in my el7 box that has no nVidia hardware.  
>> Another box, Fedora 30 with nVidia hardware is fine.
>>
>> libXNVctrl version 352.21-2 is installed.  The codes of NVCtrl.h for 
>> el7 and f30 are identical.
>>
>> I'm trying to track down a slow drift in a/v sync that I don't see on 
>> other boxes, and this looks a vaguely plausible candidate.  I don't 
>> know if the empty quotes are the problem or if it's something else.
>>
>> 2019-11-29 22:31:22.691461 I  DispResX: Raw/unsorted XRANDR modes:
>> 2019-11-29 22:31:22.691489 I  1440x900  75.00   60.00
>>
>> $ xrandr
>> Screen 0: minimum 8 x 8, current 1440 x 900, maximum 32767 x 32767
>> VGA1 connected primary 1440x900+0+0 (normal left inverted right x axis 
>> y axis) 410mm x 260mm
>>     1440x900      59.89*+  74.98
>>
>> $  mythfrontend -display VGA1 -v playback
>> qt.qpa.screen: QXcbConnection: Could not connect to display VGA1
>> Could not connect to any X display.
>>
>> Any ideas?  Thanks,
>>
>> John P
> 
> It accepts
> 
> $ mythfrontend -display :0 -v playback,timestamp --loglevel=debug
> 
> and later says
> 
> {{{
> 2019-12-02 20:33:34.758623 C  mythfrontend version: devel/2019-render 
> [v31-Pre-4fbabd9038e] www.mythtv.org
> 2019-12-02 20:33:34.758638 C  Qt version: compile: 5.9.7, runtime: 5.9.7
> 
> ====
> 
> 2019-12-02 20:33:36.800732 I  Display: Found screen 'VGA1'
> 2019-12-02 20:33:36.800764 I  Display: Using screen 'VGA1' (Make: 
> Unknown Model: Unknown)
> 2019-12-02 20:33:36.800796 I  Display: Geometry 1440x900+0+0 Size 
> 410mmx260mm
> 2019-12-02 20:33:36.801454 N  Display: Desktop video mode: 1440x900 
> 59.887 Hz
> =====
> 2019-12-02 20:33:40.355486 I  Display: New main widget
> 2019-12-02 20:33:40.355503 W  Display: Widget does not have a window!
> 2019-12-02 20:33:40.355546 I  UI Screen Resolution: 1024 x 576
> ======
> 2019-12-02 20:33:42.147155 I  DisplayX11: Raw/unsorted XRANDR modes:
> 2019-12-02 20:33:42.147183 I  1440x900  75.00   60.00
> 2019-12-02 20:33:42.147199 I  1280x1024 75.00   60.00
> ====
> 2019-12-02 20:33:42.147302 I  640x480   75.00   73.00   67.00   60.00
> 2019-12-02 20:33:42.147315 I  720x400   70.00
> 2019-12-02 20:33:42.147395 D  NVCtrl: The NV-CONTROL X extension is not 
> available on screen 0 of ':0'             ***********************
> 2019-12-02 20:33:42.148743 D  Setting 'Separate video modes for GUI and 
> TV playback' changed to 0
> 
> }}}
> 
> .. but on this box, at this commit, driving this monitor, there's still 
> a slow lipsync drift of order 1 second per hour.  I can detect it, but I 
> haven't found a logging option that is convinced.

The patch at https://code.mythtv.org/trac/ticket/13531

looks to me like a plausible cure for this a/v sync drift issue that I 
have seen in recent builds of 2019-render and master on a system without 
a working libXNVCtrl.  I have made patched rpm builds using GaryB's 
scripts in the past, but doing the patching was error prone and I'm sure 
git has a better way of doing it.  I've tried with a local copy in ~, ( 
cat <patch> | git am ) but the builds are done 'in a chroot' and the 
patching has, so far, failed...