[Openicc] XRandR and nv/nvidia was: [Re: [argyllcms] Re: ArgyllCMS Version 1.0.0 released]

[Hal V. Engel]

On Tuesday 08 July 2008 10:24:26 am Kai-Uwe Behrmann wrote:
> Am 08.07.08, 08:26 -0700 schrieb Hal V. Engel:
> > On Tuesday 08 July 2008 06:00:48 am Graeme Gill wrote:
> > > Kai-Uwe Behrmann wrote:
> > > > nv/nvidia drivers dont supports XRandR and especially 1.2.
> > > > I pinged already Aaron Plattner on the xorg list about nv and
> > > > elsewhere about the nvidia driver.
> > >
> > > Why are they claiming to then ? The Argyll XRandR 1.2 code only gets
> > > executed when XRRQueryVersion(mydisplay, &majv, &minv) returns 1.2 or
> > > greater, otherwise it falls back to the Xinerama code. With the patched
> > > code, setting the ARGYLL_IGNORE_XRANDR1_2 environment variable has 
the
> >
> > same
> >
> > > effect as the XRandR extension not being present, or returning a
> > > version < 1.2.
> > >
> > > Graeme Gill.
> >
> > According to nvidia the nv driver only has support for randr 1.2 for NV5 
> > GPUs (8xxx and 9xxx cards).  Kai-Uwe is this the type of hardware you
> > were using?
>
> It's a 6200 here.


OK then it should not have XRandR 1.2 support so it appears that the driver is 
incorrently reporting that it does have XRandR 1.2 support when it does not.  
Clearly a driver bug.


Currently the only option for nvidia hardware < NV5 for RandR 1.2 support is 
the Nouveau driver which at this point is at best Alpha level code.  It 
appears that NV4 GPUs (6xxx and 7xxx cards) have the most mature support.  But 
until these progress some more it may be problematic to use these drivers.


>
> > Nvidia's support of the video card LUTs has not been good for a long
> > time. WIth the nvidia driver you can not access the gamma tables for the
> > individual monitors if you are using "TwinView" to handle multi monitor
> > setups.  But you can if you are using Xinerama.  But you can not use any
> > of the composing setups if you are using Xinerama.  So you can have
> > either composting or correctly setup LUTs but not both.
>
> The compiz project targets at resetting the card LUT to linear and
> integrate a vcgt tag into the CLUT. Still, it should be fixed for people
> who want this feature.
>
> > I was told over a year ago by Aaron Plattner that they had an open ticket
> > to add RandR 1.2 support specifcally to address the per monitor LUT issue
> > and on the nvnews linux forums, the forum that the nvidia linux
> > developers use to interact with users, users regularly complain about
> > this issue.   Kai-Uwe have you raised the issue there?
>
> We talked on nvidia at freenode IRC.


And did he have anything useful to say?


>
> > Are the video LUT RandR 1.2 features fully functional on any video driver
> > at this point?
>
> kind regards
> Kai-Uwe Behrmann


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