[Openchrome-users] SP13000 + fuzzy vga output at high resolutions

[Xavier Bachelot]

Luc Verhaegen wrote:
> On Wed, Jan 17, 2007 at 03:13:38PM +0100, Xavier Bachelot wrote:
> 
>>brightman wrote:
>>
>>>SP13000 + fuzzy vga output at high resolutions
>>>I was thinking about buying an SP13000 board and driving the VGA output at the same resolution as my LCD which would mean a resolution of 1680 x 1050. 
>>>
>>>Firstly is this reasonably straighforward using the openchrome drivers (is there an easy way to fathom out a suitable modeline, I've used powerstrip in the past?)
>>>
>>
>>The modeline won't be hard to get. Just run 'gtf 1680 1050 60 -x' and 
>>stick the output into your xorg conf.
>>
>>
>>>Secondly I've been reading on a couple of VIA related forums about problems with the VGA output on SP13000 boards at resolutions of 1280 x 1024 (and higher). 
>>>
>>
>>However, and I don't know if it's related to the above mentioned 
>>fuzziness pb, high resolutions will require a lot of bandwidth, so the 
>>ram type you are using might come into the game.
>>
>>Regards,
>>Xavier
>>
> 
> In this case, using cvt -r might relieve the problem. 1680x1050 is a 
> resolution for a TFT based monitor, so reduced blanking should be 
> preferred if you're providing modelines anyway.
> 
> Luc Verhaegen.
> http://unichrome.sf.net/

Thx for the info, Luc. What are the differences between gtf and cvt 
apart from the reduced blanking switch ?

Is there a good explanation of reduced blanking somewhere ? I think I 
got it mostly, but would be unable to properly explain it to someone 
else. And just to be sure, can reduced blanking be used on any TFT w/o 
pb ? Using reduced blanking on a CRT simply won't work or will it also 
damage the screen ?

Regards,
Xavier