Red Hat Bugzilla – Bug 69978
Radeon failure with old VGA monitor
Last modified: 2007-04-18 12:44:44 EDT
On an ATI radeon VE supplied with the Intel i860/supermicro boards starting
XFree86 fails with the message "No monitor detected!!!". There is a standard
VGA (ancient) monitor attached to the system.
Option "CrtScreen" True
seems not to help
Created attachment 67366 [details]
Created attachment 67367 [details]
After we examined the sources, etc. I figured I'd write ATI to see if they've
got any ideas here. A config file option might be the best way to go.
Hui, any thoughts?
Date: Tue, 30 Jul 2002 09:23:06 -0400
From: Hui Yu <firstname.lastname@example.org>
To: Mike A. Harris <email@example.com>
Subject: RE: Radeon VE not detecting ancient fixed freq VGA monitor
1 Shown 43 lines Text
2 OK ~81 lines Text
If I understand correctly, the problem is that the driver quitted with "No
monitor detected!!!" message. If that's the case, it looks like the video
BIOS didn't detect it either (BIOS will use default VGA mode if nothing is
detected). Radeon driver should do the same thing too. Try this:
search for "No monitor detected" in radeon_driver.c, replace the line
followed (return FALSE;) with info->DisplayType = MT_CRT. Then the driver
will try to bring it up to standard 640x480 VGA mode if no sync range given.
Not sure how things will work out with a mono VGA.
A reminder: it's not safe to connect this old monitor with another monitor
on a different head. You might get it killed if you do so.
I think it would be plausible to add this code bit to the driver
disabled by default, but enableable via a config file option.
I get default vga mode text on the monitor. That would make sense.
This is much worse in phobe2. The installer picks the native driver the screen
times and the machine hangs dead.
I implemented a new Radeon driver config file option "ForceLegacyCRT" to
implement this change, which defaults to off.
It's in XFree86-126.96.36.1992-ati-radeon-vga-alan.patch in my
XFree86-188.8.131.522-20030218.1 build, but is untested and requires testing
on regular Radeon setups to ensure no regressions, as well as on your
VGA mono. If it works I'll leave it in for our final release. Please give
XFree86-4.2.1-11.3 has this backported now, so you can test out the
new ForceLegacyCRT option. It's in the internal errata candidate
tree for RHL 8.0.
Changing bug state to MODIFIED pending testing and final resolution. Please
change to RAWHIDE if confirmed fixed, or ASSIGNED if the new option fails.
Alan has indicated via email that this option works in rawhide X packages.
Since the similar patch is in 4.2.1 errata, closing as ERRATA.