[mythtv-users] Sync rates for Sharp 32 inch LCD

kteague@speakeasy.net kteague at speakeasy.net
Wed Jan 25 19:36:37 UTC 2006


> -----Original Message-----
> From: Richard Bronosky [mailto:mythtv at bronosky.com]
> Sent: Wednesday, January 25, 2006 06:18 PM
> To: 'Discussion about mythtv'
> Subject: Re: [mythtv-users] Sync rates for Sharp 32 inch LCD
> 
> Great info.  That should be posted everywhere that modelines are mentioned.

Since XFree86 v4.0.1, and the evolution of TV's/monitors (most modern day monitors fully comply to the latest VESA standards), EDID queries via DDC should work, and they do in most cases.  This is why it's not mentioned much, as this information should automatically be supplied from the display to the adapter and given to X.  This stuff is mentioned in the XFree86-Video-Timings-HOWTO, under the "Why is this HOWTO obsolete", but it doesn't go in to details regarding the technology.  You can find some basic information (more or less what I've already explained) by searching the web.  In addition to these standards, there is also EDDC and EEDID (extended versions).

> If I find out it does have the protections you mention above, I guess I
> could try to push the limits until it drops sync.  Then I'd know it's
> DC, H, and V sync rates. :-D

I think you're close to achieving your goal.  The tweaking you would do at this point probably wouldn't cause your display to drop sync.  It will, more or less, either extend your display width/height (overscan) or lower it (getting closer to your goal).

> It seems that There are 2 modelines in play here.  One when I chvt[1-6]
> and one that XFree86 is using on chvt7.
> How do I get my terminal [1-6] to use the new modeline? (What file is it
> using for conf?)

Unfortunately, I don't have much experience with high resolution text consoles.  I've done it once in the past, on an old 2.0 series kernel using an S3Virge (Really, I'm NOT that old! :-).  I was able to get 640x480 at 8bpp.  While booting, a logo of the Linux pinguin would be in the upper-left corner to distinguish you've got VGA text console abilities.  Anyhow, what you're looking for is SVGATextConsole.  I'm not sure if it's obsolete.  It uses kernel-level framebuffer drivers, which X doesn't use.  From what I understand, it has a config file which is similar to the X config, but I've never fiddled with it.

> All the changes I make are to /etc/X11/XF86Config-4.  Is there a way to
> modify the display mode of the boot process?
> How early can this be done?  (The BIOS screens are a pain)

This falls back to SVGATextConsole.  If it's supported by your kernel (by compling SVGA Console in to the kernel, not as a module), in the inital booting, just after the kernel is decompressed, the kernel framebuffer should kick in and switch the display mode.

- Ken




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