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-   -   Anybody knows how to change fb console refresh rate? (http://www.linuxquestions.org/questions/linux-general-1/anybody-knows-how-to-change-fb-console-refresh-rate-197248/)

iZvi 06-24-2004 01:38 PM

Anybody knows how to change fb console refresh rate?
 
I've configured LILO to load my kernel in 1024x768x64k (vga=791). it always runs with refresh rate of 60 Hz which is not very comfortable. The vert. refresh is 60 Hz in any mode 640x480, 800x600, 1024x768 (I haven't tried higher than this). In X I'm running at 1280x960x24bit@90Hz so 60Hz isn't the highest my videocard can produce. Is it possible to make my framebuffer console refresh at 75 or 85 Hz ?

natedog 06-24-2004 02:22 PM

I found out a while back, unfortunately, the VESA framebuffer refresh can't be changed -- UNLESS you want to use loadlin, and have a DOS utility for modifying the refresh rate pre-loadlin. I think the DOS prog for NVIDIA cards is called nvrefresh. I've done this, but I use X mostly now and prefer a regular boot loader.

If you want to have hi-refresh console, either use a card-specific fb driver (and if you use X too, forget the rivafb at least; no nvidia cards work with both) or the method above. Otherwise, um, just use xterms ;)

My preferred workaround is to install the ratpoison window manager (keyboard-only) and use it, and fullscreen xterms, when I want the console experience :)

And this allows multi-monitor "consoles" too, quite a bonus!

HTH,

natedog

edit: I do know other card types, especially Matrox, can have an active card-specific fb driver AND X at once. If you have a Matrox you can use boot parameters to set the refresh for sure; for others, I honestly don't know. NVIDIA and Matrox are the only cards I own, so there ya go.

iZvi 06-25-2004 11:45 AM

:( I thought it should be easier. Is this a limitation of the drivers or if the standart doesn't implement this feature?
However it isn't so bad and I can always switch to normal vga with just smaller font sizes.

natedog 06-25-2004 03:44 PM

OK,

I don't like giving a bad answer ;)
so I looked around and found this on the gentoo forums:

http://forums.gentoo.org/viewtopic.php?t=71570

and

http://dev.gentoo.org/~spock/#vesafb-tng (newer patch, but not working for ia-64)

"Getting higher refresh rates using vesafb driver"

You have to patch your (2.6) kernel, though.
It isn't exactly a simple task as you'll see by reading the linked page,
and it looks like everyone's not getting good results,
but apparently it can be done now.

I think I'm going to try this myself, when the Slackware 10 CD arrives :)

HTH,

and thanks a lot for asking the question, I wouldn't have found this otherwise!

natedog

iZvi 06-25-2004 04:17 PM

Thank you, I'll give this a try. I hope it will work with my videocard, and ... I just realised that a patch can be reversed.
It is strange to me that the kernel uses such an uncomfortable refresh rate without any chance of changing it.

iZvi 06-26-2004 08:55 AM

Actually how can I be sure what is the refresh rate..? fbset? With older versions of teh kernel it showed 60 Hz but now it shows 75 Hz for 800x600, 76 for 1024x768 and 73Hz for 640x480. But the picture is flickering as it is 60 Hz. So how can I be sure about refresh rates?


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