Red Hat Bugzilla – Bug 102244
Xwindows and console duplicated on both screens of a matrox g400
Last modified: 2007-04-18 12:56:49 EDT
From Bugzilla Helper: User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 Description of problem: Once X starts, X and consoles are duplicated on both screens of a multihead matrox g400. This is the lspci entry for the card: 01:00.0 VGA compatible controller: Matrox Graphics, Inc. MGA G400 AGP (rev 82) This is the entry in Xfree86.log: (--) PCI:*(1:0:0) Matrox Graphics, Inc. MGA G400 AGP rev 130, Mem @ 0xf6000000/25, 0xfcffc000/14, 0xfc000000/23, BIOS @ 0x80000000/1 This does not stop the card being run in xinerama mode, but it means I have to switch one monitor off if I don't want my desktop (and console) in stereo when using the default set up. Version-Release number of selected component (if applicable): How reproducible: Always Steps to Reproduce: 1. install a matrox g400 multihead 2. install redhat 3. see the duplicated screens once X starts Additional info:
I think the card is actually a g450 (although lspci shows otherwise)
For the record, I consider this misconfiguration rather than a bug. The video card detects multiple displays connected, and it enables them both at boot time. The only way to prevent that to my knowledge, is to unplug the second display. Alternatively, try looking in the "mga" man page, and possibly experiment with options that are available there. I'm not sure if there are options to control this or not, however you may also want to seek assistance solving this problem on the xfree86@xfree86.org mailing list. Both Matrox G400 and G450 both use the exact same PCI device ID, and are thus not distinguishable by the PCI device ID alone. Any software which uses the PCI device ID to look up text in a table (such as lspci, XFree86, kudzu, etc.) to translate the resultant ID into human readable text, can only display one single value. As such, both of these cards will display as Matrox G400 when using the PCI device ID alone. In order to distinguish the G400 from the G450, the subvendor and subdevice information must be looked at. If you have a real G450, the human readable text of the subdevice ID will show it to be a G450. lspci -v Another way of distinguishing the two is the chip revision number. If the revision number is 0x80 or higher, it is a G450, otherwise it is a G400. In all cases, all software internally knows the difference between the two, and properly programs the chip correctly for either G400 or G450 depending on which the chip is. Any cosmetic text displayed by the config tools, XFree86, lspci or other software, which seems misleading or to be misdetecting the chip, is in fact correct, as Matrox intentionally decided to reuse the same ID on multiple chipsets. This is confusing to end users, however it is harmless, and nothing can be done about it. In any case, XFree86 configured to use the "mga" driver will autodetect the proper Matrox chip set in all cases, and treat it properly. The X server also tests the revision and subdevice ID prior to displaying the chipset name, and properly displays "G450" for real G450 boards, whereas lspci and other hardware nonspecific tools do not. Please attach your X server config file and log file as individual uncompressed file attachments using the link below. Also, please update the report with the results of playing with the options in the manpage, and any useful tidbits you acquire from the XFree86 mailing list. Hope this helps.