[CentOS] Ignoring DDC settings on Xorg

Sun Jan 14 22:46:55 UTC 2007
first last <prelude_2_murder at yahoo.co.uk>

 --- John Summerfield <debian at herakles.homelinux.org> wrote: 
> first last wrote:
> > I am trying to set up a new 1400x900 widescreen monitor, but I just
> > cannot get it to work correctly. The closest I get is 1400x900,
> which
> > causes lots of vertical blur bands.
> 
> I am having some difficulty understanding the difference between 
> 1400x900 and 1400x900.

Apologies. It is 1400x900 (physical) and 1440x900 (the one that xorg
chooses).

> > I have tried with two different machines with i945 and ATi cards,
> > running CentOS 4 and Ubuntu, always with the same result.
> 
> My experience with Intel graphics is it's usually difficult; I have a
> 
> Dell GX270 with onboard Intel graphics and, in FC6, it doesn't work
> at 
> in any useful sense. (Note, with coaxing, it works in EL5 beta, SLES
> and 
> SUSE 10.1). And that's with a monitor running at  1280x1024.

I had to use 915resolution to enable the modes on the BIOS. It seems to
work fine for all the other resolutions I set, but it seems that being
so close to the other "standard" resolution messes xorg up.

> > 
> > My investigations indicate that the monitor reports itself to be
> > "1440x900". It also supports 1600x1200 by squashing the pixels
> > together, so it also advertises support for that resolution, which
> > messes things up.
> > 
> > According to the documentation I have seen online, disabling DDC
> (using
> > NoDDC and DCC "off") and setting the correct modeline should work,
> but
> > it always reverts to 1440x900 (if I am lucky).
> > 
> > Any ideas on how to force it to the right resolution? It really is
> > driving me nuts not being able to use the monitor to the native
> > resolution.
> 
> You could try reading the messages written to the Xorg log file in
> /var/log

You can see things like:
(... )
(**) I810(0): Option "NoDDC"
(... )
Mode: 3a (1400x900)
        ModeAttributes: 0x9b
        WinAAttributes: 0x7
        WinBAttributes: 0x0
        WinGranularity: 64
        WinSize: 64
        WinASegment: 0xa000
        WinBSegment: 0x0
        WinFuncPtr: 0xc00076a3
        BytesPerScanline: 1408
        XResolution: 1400
        YResolution: 900
        XCharSize: 8
        YCharSize: 16
        NumberOfPlanes: 1
        BitsPerPixel: 8
        NumberOfBanks: 1
        MemoryModel: 4
        BankSize: 0
        NumberOfImages: 9
        RedMaskSize: 0
        RedFieldPosition: 0
        GreenMaskSize: 0
        GreenFieldPosition: 0
        BlueMaskSize: 0
        BlueFieldPosition: 0
        RsvdMaskSize: 0
        RsvdFieldPosition: 0
        DirectColorModeInfo: 0
        PhysBasePtr: 0xc0000000
        LinBytesPerScanLine: 1408
        BnkNumberOfImagePages: 9
        LinNumberOfImagePages: 9
        LinRedMaskSize: 0
        LinRedFieldPosition: 0
        LinGreenMaskSize: 0
        LinGreenFieldPosition: 0
        LinBlueMaskSize: 0
        LinBlueFieldPosition: 0
        LinRsvdMaskSize: 0
        LinRsvdFieldPosition: 0
        MaxPixelClock: 230000000
Mode: 3c (1400x900)
        ModeAttributes: 0x9b
        WinAAttributes: 0x7
        WinBAttributes: 0x0
        WinGranularity: 64
        WinSize: 64
        WinASegment: 0xa000
        WinBSegment: 0x0
        WinFuncPtr: 0xc00076a3
        BytesPerScanline: 1408
        XResolution: 1400
        YResolution: 900
        XCharSize: 8
        YCharSize: 16
        NumberOfPlanes: 1
        BitsPerPixel: 8
        NumberOfBanks: 1
        MemoryModel: 4
        BankSize: 0
        NumberOfImages: 9
        RedMaskSize: 0
        RedFieldPosition: 0
        GreenMaskSize: 0
        GreenFieldPosition: 0
        BlueMaskSize: 0
        BlueFieldPosition: 0
        RsvdMaskSize: 0
        RsvdFieldPosition: 0
        DirectColorModeInfo: 0
        PhysBasePtr: 0xc0000000
        LinBytesPerScanLine: 1408
        BnkNumberOfImagePages: 9
        LinNumberOfImagePages: 9
        LinRedMaskSize: 0
        LinRedFieldPosition: 0
        LinGreenMaskSize: 0
        LinGreenFieldPosition: 0
        LinBlueMaskSize: 0
        LinBlueFieldPosition: 0
        LinRsvdMaskSize: 0
        LinRsvdFieldPosition: 0
        MaxPixelClock: 230000000
(same resolution for modes 4b, 4d, 5a, 5c in the bios, no mention to
1400x900)
(... )
(II) I810(0): Correcting stride (1400 -> 5632)
(II) I810(0): Increasing the scanline pitch to allow tiling mode (1408
-> 2048).
(--) I810(0): Virtual size is 1400x900 (pitch 2048)
(**) I810(0):  Built-in mode "1400x900"
(**) I810(0):  Built-in mode "1400x900"
(**) I810(0):  Built-in mode "1280x800"
(**) I810(0):  Built-in mode "1024x768"
(**) I810(0):  Built-in mode "800x600"
(**) I810(0):  Built-in mode "640x480"
(II) I810(0): Attempting to use 60.00Hz refresh for mode "1400x900"
(85a)
(II) I810(0): Attempting to use 60.00Hz refresh for mode "1400x900"
(85c)
(II) I810(0): Attempting to use 60.00Hz refresh for mode "1280x800"
(858)
(II) I810(0): Attempting to use 60.00Hz refresh for mode "1024x768"
(854)
(II) I810(0): Attempting to use 60.32Hz refresh for mode "800x600"
(852)
(II) I810(0): Attempting to use 60.00Hz refresh for mode "640x480"
(850)
(.. it then loads ddc... for some unknown reason... )
(II) Open ACPI successful (/var/run/acpid.socket)
(II) AIGLX: Resuming AIGLX clients after VT switch
(II) I810(0): xf86BindGARTMemory: bind key 8 at 0x007bf000 (pgoffset
1983)
(II) I810(0): xf86BindGARTMemory: bind key 0 at 0x0ffff000 (pgoffset
65535)
(II) I810(0): xf86BindGARTMemory: bind key 1 at 0x0fffb000 (pgoffset
65531)
(II) I810(0): xf86BindGARTMemory: bind key 3 at 0x0ffea000 (pgoffset
65514)
(II) I810(0): xf86BindGARTMemory: bind key 2 at 0x0fffa000 (pgoffset
65530)
(II) I810(0): xf86BindGARTMemory: bind key 4 at 0x0ffe2000 (pgoffset
65506)
(II) I810(0): xf86BindGARTMemory: bind key 5 at 0x0f000000 (pgoffset
61440)
(II) I810(0): xf86BindGARTMemory: bind key 6 at 0x0e800000 (pgoffset
59392)
(II) I810(0): xf86BindGARTMemory: bind key 7 at 0x0c380000 (pgoffset
50048)
(II) Loading sub module "ddc"
(II) LoadModule: "ddc"
(II) Reloading /usr/lib/xorg/modules/libddc.so
(lists the modes again, no mention of 1440x900)

That's it, not a single mention of "1440x900", but it still loads X
using that resolution.

I am really puzzled as of why it would do this, apart from the fact
that it is getting the data from the monitor.

The output of ddcprobe is:
vbe: VESA 3.0 detected.
oem: Intel(r) 82945GM Chipset Family Graphics Chip Accelerated VGA BIOS
vendor: Intel Corporation
product: Intel(r) 82945GM Chipset Family Graphics Controller Hardware
Version 0.0
memory: 12288kb
mode: 1280x1024x256
mode: 1280x1024x64k
mode: 1280x1024x16m
mode: 1024x768x256
mode: 1024x768x64k
mode: 1024x768x16m
mode: 640x480x16m
mode: 800x600x64k
mode: 800x600x16m
mode: 640x480x256
mode: 800x600x256
mode: 640x480x64k
edid:
edid: 1 3
id: 0000
eisa: NUL0000
serial: 00000001
manufacture: 30 2006
input: sync on green, analog signal.
screensize: 41 26
gamma: 2.200000
dpms: RGB, no active off, no suspend, no standby
timing: 720x400 at 70 Hz (VGA 640x400, IBM)
timing: 720x400 at 88 Hz (XGA2)
timing: 640x480 at 67 Hz (Mac II, Apple)
timing: 640x480 at 75 Hz (VESA)
timing: 800x600 at 60 Hz (VESA)
timing: 800x600 at 75 Hz (VESA)
timing: 832x624 at 75 Hz (Mac II)
timing: 1024x768 at 87 Hz Interlaced (8514A)
timing: 1024x768 at 75 Hz (VESA)
timing: 1280x1024 at 75 (VESA)
dtiming: 1440x900 at 69 <- What's this... should be 1400x900 at 60
monitorid:
monitorname: M19W
monitorserial:

I have tried everything I can think of, but to no avail (now including
FC6). so any help would be appreciated.

Gabriel


	
	
		
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