Nouveau - Aug 2019 - unstable refresh rate

Can you try something very simple - unplug the cable, and plug it back
in, while the TV is on, and set to the HDMI input? That should ensure
that the SCDC write can go through at modeset time.

You can also force nouveau to avoid any modes that require scrambling
by booting with nouveau.hdmimhz=340.

Cheers,

  -ilia

On Tue, Aug 6, 2019 at 1:15 PM James <bjlockie at lockie.ca>
wrote:
>
> I was going to buy a new cable and I came across this description:
>  >Category 2 Certified HDMI wire supports resolutions up to 4Kx2K (UHD)
> @30 Hz
>
> https://www.cnet.com/how-to/what-is-hdmi-2-0b/
> > HDMI versions compared
> > HDMI Version  Max Resolution  Max 4K Frame rate       HDCP 2.2       
HDR     WCG     Hybrid Log Gamma        Dynamic Metadata
> > 1.4   4K      30Hz    No      No      No      No      No
> > 2.0   4K      60Hz    Yes     No      No      No      No
> > 2.0a  4K      60Hz    Yes     Yes     Yes     No      No
> > 2.0b  4K      60Hz    Yes     Yes     Yes     Yes     No
> > 2.1   10K     120Hz   Yes     Yes     Yes     Yes     Yes
>
> "Category 2" implies HDMI 2 but the "Max 4K Frame rate"
of 30Hz says it
> is HDMI-1.4.
>
> _______________________________________________
> Nouveau mailing list
> Nouveau at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/nouveau

On August 6, 2019 1:36:09 p.m. Ilia Mirkin <imirkin at alum.mit.edu>
wrote:
> Can you try something very simple - unplug the cable, and plug it back
> in, while the TV is on, and set to the HDMI input?
I still only get 30Hz.
I did just update the tv firmware s9 maybe that is why I can't get it 60Hz 
anymore.
I wish I kept better track of the timeline.

With the new HDMI 2 cable I get 4096x2160 at 30Hz (there is no 60Hz option).
3840x2160 at 59.9685Hz gives me no signal.

> That should ensure
> that the SCDC write can go through at modeset time.
>
> You can also force nouveau to avoid any modes that require scrambling
> by booting with nouveau.hdmimhz=340.
>
> Cheers,
>
>  -ilia
>
> On Tue, Aug 6, 2019 at 1:15 PM James <bjlockie at lockie.ca> wrote:
>>
>> I was going to buy a new cable and I came across this description:
>>> Category 2 Certified HDMI wire supports resolutions up to 4Kx2K
(UHD)
>> @30 Hz
>>
>> https://www.cnet.com/how-to/what-is-hdmi-2-0b/
>>> HDMI versions compared
>>> HDMI Version  Max Resolution  Max 4K Frame rate       HDCP 2.2     
HDR
>>>   WCG     Hybrid Log Gamma        Dynamic Metadata
>>> 1.4   4K      30Hz    No      No      No      No      No
>>> 2.0   4K      60Hz    Yes     No      No      No      No
>>> 2.0a  4K      60Hz    Yes     Yes     Yes     No      No
>>> 2.0b  4K      60Hz    Yes     Yes     Yes     Yes     No
>>> 2.1   10K     120Hz   Yes     Yes     Yes     Yes     Yes
>>
>> "Category 2" implies HDMI 2 but the "Max 4K Frame
rate" of 30Hz says it
>> is HDMI-1.4.
>>
>> _______________________________________________
>> Nouveau mailing list
>> Nouveau at lists.freedesktop.org
>> https://lists.freedesktop.org/mailman/listinfo/nouveau

I think I may have updated the tv firmware between when it worked and 
when it didn't.
I wonder it it has to do with bit depth.
I use lubuntu and it doesn't let me pick the bit depth so I don't know 
what it using.