Linux hp Z book 10 bits

1
Dear Mario
A preliminary report. I ran my test program on my Linux hp. It shows 10 but luminance precision. I can't send the graph yet because I don't know how to do email in Linux.

What is the magic number for dither on this computer? I don't know the exact model but it's a Z Book. Same computer that hornet wrote to you about.

I was surprised by a limitation. On macOS I enable Clut mapping with 4096 Clut size. Works fine. In Linux if the requested Clut size is larger than 256 the call to loadnormalizedgammatable with load=2 gives a fatal error complaining that my Clut is bigger than 256. Seems weird since it was already told when I enabled that I'd be using a 256 element soft Clut.

Best
Denis

Sent from my iPhone
2
On 04/06/2017 02:56 AM, Denis Pelli wrote:
> Dear Mario A preliminary report. I ran my test program on my Linux
> hp. It shows 10 but luminance precision. I can't send the graph yet
> because I don't know how to do email in Linux.
>
> What is the magic number for dither on this computer? I don't know
> the exact model but it's a Z Book. Same computer that hornet wrote to
> you about.
>
> I was surprised by a limitation. On macOS I enable Clut mapping with
> 4096 Clut size. Works fine. In Linux if the requested Clut size is
> larger than 256 the call to loadnormalizedgammatable with load=2
> gives a fatal error complaining that my Clut is bigger than 256.
> Seems weird since it was already told when I enabled that I'd be
> using a 256 element soft Clut.
>

I don't understand that? What kind of clut mapping with load=2? On Linux
the driver uses the discrete 256 slot hardware gamma table, instead of
the non-linear gamma mapping that macOS now uses. Also PTB on Linux
completely disables hw gamma tables in >= 10 bit modes, so all gamma
correction is done via PsychColorCorrection(). You start off with a
identity gamma table.

> Best Denis
>
> Sent from my iPhone
>