[ltp] DVI problem again

[Alex Deucher]

On 11/17/05, Dragos Vingarzan <vingarzan@fokus.fraunhofer.de> wrote:
> You are right Alex.
> Found at http://www.ati.com/products/radeon7500/radeon7500/faq.html this:
>
>  What is the speed of the TMDS transmitter for driving a DVI-I based
> digital flat panel monitor and what is the maximum resolution?
> A20:     Radeon(r) 7500 supports a 165MHz TMDS transmitter and can reach
> resolutions of up to 1600x1200. DVI resolution and refresh support is
> dependant upon DDC signals from the monitor. Some resolution and refresh
> rate restrictions may occur depending upon the signals sent from the
> monitor.
>
> So the chip can do it, no doubt.Also here it says that it can do  LVDS +
> DVI + CRT in parallel:
> http://www.ati.com/products/embedded/mobilityradeon750032/features.html
>

The r128s and all r1xx-r4xx radeons all have pretty much the same
display engine.  only the new avivo based radeons (r5xx) have a
radically different setup.  With some variation, most have two 400 Mhz
DACs, one 165 Mhz TMDS controller, one LVDS controller, a tv-encoder,
and two crtcs.

> But then, if it works, why would IBM lock it from the windows drivers?
> This is my main argument that it is a hardware limitation.

OEMs do a lot of strang things.  some OEM drivers disable dualhead,
power management features, etc.  Some just don't wire up ports.=20
several thinkpads lack TV-out even though all recent ati chips have an
integrated tv-encoder.  Apple disabled dualhead in on ibooks even
though the radeons and r128s support it. They only let you use it on
powerbooks.  IBM either made some marketing decision to do it or
perhaps the way they actually wired up the ports between the actual
leads on the chip and the actual ports.  It could be the length of the
run or that they used cheaper resisters and such to wire it up.

Alex

>
> It smells like a strategic decision so that the 7500 won't compete with
> the higher models in desktop usage... I, for one, don't feel the
> performance difference from M7 to M24 in eclipse, but I surely needed
> the higher resolution and I switched.
>
> -Dragos-
>
> Alex Deucher wrote:
>
> >On 11/17/05, Dragos Vingarzan <vingarzan@fokus.fraunhofer.de> wrote:
> >
> >
> >> From my T42 with the 7500 and trying with different hi-res LCDs:
> >>1. The DVI can't drive displays with a res >1280x1024.
> >>2. The DVI and LCD do not work in parallel - maybe it's the same
> >>circuit, because I could never turn them both on.
> >>
> >>As with the windows drivers it's the same, I think those are limitation
> >>of the 7500...
> >>
> >>With the T43p and the V3200 (M24) it is quite easy to go over both prob=
lems.
> >>
> >>
> >>
> >
> >It's definitely not a limitation of the chip (the display cells on the
> >radeons have been roughly the same since the r128 days), however, how
> >IBM wired it up is another matter...
> >
> >Alex
> >
> >
> >
> >>Cheers,
> >>Dragos
> >>
> >>Martin H=F6fling wrote:
> >>
> >>
> >>
> >>>I still could not solve the following problem: Samsung 20'' 1600x1200
> >>>connected to the DVI port of my dock. Radeon 7500 Mobility in a T40 (r=
adeon
> >>>driver):
> >>>
> >>>-Analog 1600x1200 is working flawless (Windows & Linux)
> >>>-DVI hangs (linux) or shows 1280x1024(Windows) 1600x1200 only scrollin=
g (I
> >>>assume it's the IBM-Windows software encoded limitation)
> >>>-I tried to add modelines to my monitorsection, both are working in an=
alog
> >>>mode with 60Hz output
> >>>       Modeline        "1600x1200" 162.00 1600 1664 1856 2160   1200 1=
201
> >>>1204 1250
> >>>       Modeline        "1024x768"  60.80  1024 1056 1128 1272   768  7=
68  770
> >>>796
> >>>
> >>>-another question which has nothing to do with the problem: xrandr rot=
ation is
> >>>not working
> >>>
> >>>I provided some (hopefully useful) information, thanks for help.
> >>>      Martin
> >>>
> >>>martin@arrakis ~ $ xrandr -q
> >>>SZ:    Pixels          Physical       Refresh
> >>>0   1024 x 768    ( 411mm x 311mm )   0
> >>>*1   1600 x 1200   ( 411mm x 311mm )  *0
> >>>Current rotation - normal
> >>>Current reflection - none
> >>>Rotations possible - normal
> >>>Reflections possible - none
> >>>
> >>>martin@arrakis ~ $ X -version
> >>>
> >>>X Window System Version 6.8.2
> >>>Release Date: 9 February 2005
> >>>X Protocol Version 11, Revision 0, Release 6.8.2
> >>>Build Operating System: Linux 2.6.12 i686 [ELF]
> >>>Current Operating System: Linux arrakis 2.6.14.1 #1 PREEMPT Sun Nov 13
> >>>20:44:34 CET 2005 i686
> >>>Build Date: 19 September 2005
> >>>       Before reporting problems, check http://wiki.X.Org
> >>>       to make sure that you have the latest version.
> >>>Module Loader present
> >>>
> >>>xorg.conf is attached.
> >>>
> >>>
> >>>
> >>>
> >>>
> >>--
> >>The linux-thinkpad mailing list home page is at:
> >>http://mailman.linux-thinkpad.org/mailman/listinfo/linux-thinkpad
> >>
> >>
> >>
>
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