[mythtv-users] Mythbuntu 16.04 and nvidia drivers

Fri Dec 9 08:17:55 UTC 2016

Hi again,

 Bottom posting again for forum compatibility...
On Thursday, December 8, 2016 20:46 CET, Klaas de Waal <klaas.de.waal at gmail.com> wrote:
 Mythbuntu with nvidia driver 367.57 gives the same frame rate problem on my GT520 card. Downgrading to nvidia driver 340.98 with the "Software & Updates" app of Ubuntu solves the problem. The puzzling part is that if you manually specify a framerate with xrandr, e.g. "sudo xrandr --display :0 --rate 51" with the rate from 50 to 64, each rate value gives the same frequency setting for both drivers. This suggests it could be a change in the binary interface to the driver that causes MythTV to set the wrong frequency.  On Wed, Dec 7, 2016 at 9:39 PM, klaas de waal <klaas at kldo.nl> wrote:Mythbuntu with nvidia driver 367.57 gives the same frame rate problem on my GT520 card. Downgrading to nvidia driver 340.98 with the "Software & Updates" app of Ubuntu solves the problem. The puzzling part is that if you manually specify a framerate with xrandr, e.g. "sudo xrandr --display :0 --rate 51" with the rate from 50 to 64, each rate value gives the same frequency setting for both drivers.   On Wed, Dec 7, 2016 at 5:55 PM, John Finlay <finlay at moeraki.com> wrote:On 12/7/2016 3:04 AM, Hika van den Hoven wrote:
> Hoi John,
>
> Wednesday, December 7, 2016, 10:19:14 AM, you wrote:
>
>
>
>> On 12/06/2016 11:15 PM, Marius Schrecker wrote:
>>> Thanks Hika,
>>>
>>> On Tuesday, December 6, 2016 17:43 CET, Hika van den Hoven
>>> <hikavdh at gmail.com> wrote:
>>>
>>>> Hoi Marius,
>>>>
>>>> Tuesday, December 6, 2016, 10:48:03 AM, you wrote:
>>>>
>>>>> Hi,
>>>>> ARound the time that 16.04 came out I did an upgrade of an older
>>>>> mythbuntu system with a GT610 video adapter and hit problems with
>>>>> the nvidia nv-control module, which wasn't allowing mythtv to match
>>>>> the monitor refresh rate to the frame rate of the content I was
>>>> trying to play.
>>>>
>>>>> I tried "everything" at the time, using all the available versions
>>>>> I could easily install using packages, scripted installers and
>>>>> vanilla nvidia installer, all with no success. I eventually gave up
>>>>> and lived with the problem, allowing the available drivers,
>>>>> packages, mythtv code to mature over time before trying again.
>>>>> I haven't had much time since to play with mythtv, but last night,
>>>>> for the hell of it, after being irritated again with the jumpy
>>>>> video, I decided to downgrade from the version that was installed (I
>>>>> can't remember now whether it was 358, 361 or 364) to 340, which was
>>>>> mentioned in another recent thread regarding a working driver for
>>>> legacy cards.
>>>>
>>>>> I rebooted and was surprised and pleased to see that the refresh
>>>>> rates were now being set correctly... Problem solved!
>>>>> However, as we have now moved on quite a bit since April and as
>>>>> there are newer driver versions available, does anyone know if
>>>>> something changed radically since 340 in the way Nvidia handles
>>>> refresh rates?
>>>>
>>>>> Can anyone say which driver version might now be considered optimal
>>>> for the GT610 on a mythTV system?
>>>>
>>>>> I'm a bit wary about breaking again whatever fixed itself
>>>>> yesterday, so don't want to just blindly cycle through the driver
>>>> versions.
>>>>
>>>>> BR.
>>>>> --Marius--
>>>>>
>>>>
>>>> http://www.nvidia.com/object/IO_32667.html
>>>>
>>> Hmm, so the GT 610 isn't there as it's not considered lagacy hardware.
>>> All the same, the driver seems to work far better than the version I
>>> had installed before. At least when it comes to updating refresh rates.
>>>
>>> Any other GT610 users out there:Please can you say which nvidia driver
>>> you're using with Myth?
>>>
>>>  Thanks
>>>
>> I have a FE with a GT610 that successfully uses the 367.57 driver in
>> Mythbuntu 16.04.
>> John
>> _______________________________________________
> Ah, but Nvidia itself does not guaranty that! If I remember correct
> they place it as a 340 legacy card. It's some time ago I
> used/installed a GT610. I guess you will see warnings in your bootlog
> about things not working properly.
>
>
>
 The 367.57 was the driver installed by Mythbuntu 16.04 during
installation. I had to install 16.04 from scratch since the upgrade from
14.04 failed miserably. I checked the log and I don't see any error
messages and from my use so far it looks good. When using 14.04 I was
using 340.98 and it also worked well.

John_______________________________________________
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Hi Klaas,

 yes. The framerate problem puzzles me too. I posted about it in:

http://www.gossamer-threads.com/lists/mythtv/users/599030?search_string=nv-control;#599030

The problem seems to be to do with the NV-CONTROL module in later driver versions, which seems to be incompatible with MythTV's way of changing the framerate (at least with some builds). What is really strange is that many people seem not to experience the problem, which is why I tried so hard to build from scratch, use scripted installers and as many different nvidia package repositories as I could find back in April. Trying again now it is clear that 340 doesn't have the problem, while anything later does (at least on my system).

I can't remember who it was, but someone on the forum suggested that it has to do with the way the driver reports the framerates, with later drivers reporting the actual framerate in decimal values, while MythTV is coded to work with the false refresh rates, which are integer values.  If I remember rightly, the only way around this was to add support for later versions of RandR, which handle the decimnal values (that's why you can change the refresh rate from xRandR, but not from MythTV.

It's possible that teh solution is as simple as an extra xorg.conf flag, to tekll the driver to report the refresh rates the old fashioned way, as integers....

 Anyway, that's my non-technical, half-remembered take on the problem. Someone else will surely be able to correct my understanding or explain it more correctly.

For now, I'm back with 340.xx which handles refresh rates fine, but which has another annoying problem:

  I loose the TV (HDMI connection) whenever I turn it off, then back on again, while leaving the Mythbox running. In later drivers I can make it work by referencing a local Edid file from xorg.conf. In 340 it doesn't seem to work and I have to do a xrandr --auto to kick it back to life. Maybe someone knows how to fix that too??

Cheers!

--Marius--

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