Modelines and DVI-D output

[Roland Scheidegger]

Morten Sylvest Olsen wrote:
> Hi list..
> 
> Is anybody here a world champion in modelines? :) How exactly does
> modelines make a difference when driving TFT monitors over a DVI-D link?
> Obviously the different timings related to beam retracing etc. have no
> physical meaning.
> 
> The reason I am asking is that I have a TFT monitor that simply refuses
> to show anything at all. The monitor is a Barco E-3220 which is a
> "medical" type greyscale monitor with resolution 1536x2048. The monitor
> supports EDID and returns a modeline, which X uses but the monitor is
> never able to sync on the signal.
> 
> Modeline "1536x2048"  200.00  1536 1564 1580 1584  2048 2088 2120 2152
> 
> The graphics board is an ATI FireGL V7100 (using the binary driver
> though, but don't know if that really matters)
> 
> I would not put it past them to return crap in the EDID, since they try
> to sell hideously overpriced "medical" graphics board together with
> their monitors.
> 
> A previous monitor of theirs return EDID data 2048x1536: 
> 
> Modeline "2048x1536" 200.4  2048 2096 2156 2152 1536 1537 1557 1558
>                                            ^^^^
> where h_blank_end is before h_sync_end. That *must* be bogus, right? 
> 
> Hope somebody is able to shed a bit of light on this.

I'm no expert on modelines, but 200Mhz pixel clock is only possible with 
dual-link dvi. Your card has one dual-link and one single-link dvi 
connector, thus you need to use the correct one.
I have no idea if fglrx (you'd need to ask ati about that) or the 
open-source radeon driver can actually handle the external dual-link 
tmds transmitter the fglrx cards have.
You also _might_ be able to drive the monitor with a single-link dvi 
connector, if you use a modeline with 165Mhz pixel clock (this would 
reduce the vertical refresh rate to around 45Hz or so, it depends on the 
monitor's input logic if it accepts that or not).

Roland