Cannot get 75hz on TFT monitor (via DVI)

[Alex Deucher]

On 10/31/05, Erik Ahlner <whyz at home.se> wrote:
> Alex Deucher wrote:
>
> >On 10/31/05, Björn Nilsson <bni.swe at gmail.com> wrote:
> >
> >
> >>I have a ViewSonic VP171S TFT monitor, and radeon 9200SE, and I get about
> >>the same results as you. xvidtune doesnt lie to me though, it reports 60 Hz.
> >>OSD reports 60Hz. In Windows XP I can use 75Hz if I want (I think its
> >>default), but I have not noticed any difference in display quality either
> >>way. I have not tried with VGA cable like you.
> >>
> >>
> >>
> >
> >IIRC, the radeon driver rejects user specified modelines for DVI.
> >
> >Alex
> >
> >
>
> Could this be the case for the Nvidia drivers too? (both nv and nvidia)
>

I don't know.  I'm not even sure the nv driver really officially fully
supports DVI.

Alex

> Erik
>
> >
> >
> >>On 10/31/05, Erik Ahlner <whyz at home.se> wrote:
> >>
> >>
> >>>Michel Dänzer wrote:
> >>>
> >>>
> >>>
> >>>>On Fri, 2005-10-28 at 17:26 +0200, Erik Ahlner wrote:
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>>I switched to nv driver instead of nvidia just to be certain that it
> >>>>>wasn't the drivers fault, but that made no difference. I still got 60hz.
> >>>>>
> >>>>>BUT:
> >>>>>My monitor has 2 inputs,one DVI and one VGA. So does the gfx.
> >>>>>I switched to VGA cable, which instantly (without changing any settings
> >>>>>at all) gave me 75hz!
> >>>>>So, there's something jiffy about DVI.. it works in 75hz in windows, but
> >>>>>in Xorg, it just gives me 60.
> >>>>>
> >>>>>
> >>>>>
> >>>>>
> >>>>The panel probably runs at 60 Hz anyway, so that should be ideal.
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>>
> >>>No, it does *not* run at 60hz. There's a VERY noticable difference
> >>>between the two. Easy way to check:
> >>>60hz (DVI) gives me tearing when running the game at maxfps 60 (because
> >>>fps rate similar to refresh rate tends to give tearing). I only need to
> >>>adjust it a few hz from 60 and it is smooth.
> >>>75hz (VGA only atm :(() looks good at maxfps 77, which is the only fps
> >>>rate i can use to maintain the physics of the game (yeah, i know it's
> >>>stupid). Plus: the On Screen Display menu of the monitor tells me what
> >>>the refresh rate is, as I earlier posted:
> >>>
> >>>
> >>http://whyz.mine.nu/imgp6252.jpg
> >>
> >>
> >>>Anyway, this is not the question whether it's sufficient for me or not,
> >>>it's a serious BUG imo. The monitor handles 75hz (According to specs,
> >>>which also has been successfully used in Windows via DVI and in Linux
> >>>only via VGA), but Xorg refuses to deliver 75hz via DVI!
> >>>With no changes whatsoever to xorg.conf, just switching from DVI
> >>>output&input to VGA output&input, I get 75Hz.
> >>>
> >>>So, is there ANYONE that has successfully used more than 60hz via DVI
> >>>using xorg in this list? Am i the only one that thinks it's weird?
> >>>
> >>>Kind regards,
> >>>Erik Ahlner
> >>>
> >>>
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> >>>
> >>>
> >>>
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> >>
> >>
> >>
> >>
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> >
> >
> >
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