DDC: no ddc bus - possible BIOS bug
alexdeucher at gmail.com
Thu Dec 30 08:46:31 PST 2010
On Thu, Dec 30, 2010 at 10:25 AM, 屋国遥 <hyagni at gmail.com> wrote:
> Hello, all.
> I am trying to make dual-head environment on Mac Pro with Ubuntu
> 10.10. My Mac Pro has the Radeon HD 2600 XT graphic card, so I decided
> to use the radeon driver.
> Now, I connect two monitors (the same SAMSUNG monitors) and boot the
> system and X, one display works well, but the other is not recognized.
> In dmesg, I found out the following error message.
> I googled the message and found
> and <https://bugs.freedesktop.org/show_bug.cgi?id=29255>. Referring
> to these posts, I upgraded the kernel to 2.6.36
> (http://kernel.ubuntu.com/~kernel-ppa/mainline/v2.6.36-maverick/) and
> also graphic drivers (https://launchpad.net/~xorg-edgers/+archive/ppa).
> However, the same error is displayed.
> I am sorry to say that I have no idea how to use Alex's patch to
> `radeon_atombios.c' because of my poor knowledge of Linux.
> Is not this change included in the recent kernel or drivers?
> Because dual-head environment works successfully on Mac, I suspect the
> monitor or graphic card has no problem.
You will need a custom patch for your system. That patch referenced
in the above thread only applies to evergreen chips. I suspect apple
forgot to specify the ddc assignment for one of the heads in their
vbios and their driver most likely use hardcoded values. Please send
me a copy of the vbios from your system, and I'll send you a patch to
fix it. Also please attach the pci device and subsystem ids for your
card (lspci -vnn). Also, what connectors does your card actually
have? Two DVI-I? Two DVI-I and one TV-out? It looks like some of
the encoder mapping might be wrong on your system too. I can help get
that fixed up as well.
To get the vbios:
(use lspci to get the bus id)
cd /sys/bus/pci/devices/<pci bus id>
echo 1 > rom
cat rom > /tmp/vbios.rom
echo 0 > rom
> The following is some display-related information and settings.
> I tried to attach video bios data, but I could not, because echo and cut are
> permission denied (of course, I did them as root).
> Thank you.
> $ dmesg | grep drm
> [ 11.044447] [drm] Initialized drm 1.1.0 20060810
> [ 11.490963] [drm] radeon kernel modesetting enabled.
> [ 11.491845] [drm] initializing kernel modesetting (RV630 0x1002:0x9588).
> [ 11.491928] [drm] register mmio base: 0x90A20000
> [ 11.491930] [drm] register mmio size: 65536
> [ 11.493649] [drm] Detected VRAM RAM=256M, BAR=256M
> [ 11.493650] [drm] RAM width 128bits DDR
> [ 11.493745] [drm] radeon: 256M of VRAM memory ready
> [ 11.493746] [drm] radeon: 512M of GTT memory ready.
> [ 11.493817] [drm] radeon: irq initialized.
> [ 11.493820] [drm] GART: num cpu pages 131072, num gpu pages 131072
> [ 11.494334] [drm] Loading RV630 Microcode
> [ 11.644264] [drm] ring test succeeded in 1 usecs
> [ 11.644404] [drm] radeon: ib pool ready.
> [ 11.644465] [drm] ib test succeeded in 0 usecs
> [ 11.644468] [drm] Enabling audio support
> [ 11.644951] [drm] Radeon Display Connectors
> [ 11.644952] [drm] Connector 0:
> [ 11.644954] [drm] DVI-I
> [ 11.644955] [drm] DDC: no ddc bus - possible BIOS bug - please
> report to xorg-driver-ati at lists.x.org
> [ 11.644956] [drm] Encoders:
> [ 11.644957] [drm] CRT2: INTERNAL_KLDSCP_DAC2
> [ 11.644959] [drm] TV1: INTERNAL_KLDSCP_DAC2
> [ 11.644960] [drm] DFP1: INTERNAL_KLDSCP_TMDS1
> [ 11.644961] [drm] Connector 1:
> [ 11.644962] [drm] DVI-I
> [ 11.644963] [drm] HPD2
> [ 11.644965] [drm] DDC: 0x7e40 0x7e40 0x7e44 0x7e44 0x7e48 0x7e48
> 0x7e4c 0x7e4c
> [ 11.644966] [drm] Encoders:
> [ 11.644968] [drm] CRT1: INTERNAL_KLDSCP_DAC1
> [ 11.644969] [drm] DFP2: INTERNAL_LVTM1
> [ 11.696891] [drm] Internal thermal controller with fan control
> [ 11.696947] [drm] radeon: power management initialized
> [ 11.807426] [drm] fb mappable at 0x80141000
> [ 11.807427] [drm] vram apper at 0x80000000
> [ 11.807429] [drm] size 5242880
> [ 11.807430] [drm] fb depth is 24
> [ 11.807431] [drm] pitch is 5120
> [ 12.225159] fb0: radeondrmfb frame buffer device
> [ 12.225160] drm: registered panic notifier
> [ 12.225172] [drm] Initialized radeon 2.6.0 20080528 for
> 0000:02:00.0 on minor 0
> $ cat /etc/X11/xorg.conf
> Section "Module"
> Load "glx"
> Section "Monitor"
> Identifier "vga2"
> Option "DPMS" "true"
> Option "LeftOf" "vga1"
> Option "Enable" "true"
> Section "Monitor"
> Identifier "vga1"
> Option "DPMS" "true"
> Section "Device"
> Identifier "Radeon HD 2600 XT"
> Driver "radeon"
> BusID "PCI:2:0:0"
> Option "monitor-VGA1" "vga1"
> Option "monitor-VGA2" "vga2"
> Section "Screen"
> Identifier "Default Screen"
> Device "Default Device"
> Monitor "vga1"
> DefaultDepth 24
> SubSection "Display"
> Virtual 2560 1024
> $ uname -a
> Linux username-MacPro 2.6.36-020636-generic #201010210905 SMP Thu Oct
> 21 10:17:53 UTC 2010 i686 GNU/Linux
> <by some reason, i replaced username with "username">
> $ lspci | grep VGA
> 02:00.0 VGA compatible controller: ATI Technologies Inc RV630 [Radeon HD 2600XT]
> $ xrandr -q
> Screen 0: minimum 320 x 200, current 1280 x 1024, maximum 8192 x 8192
> DVI-0 disconnected (normal left inverted right x axis y axis)
> DVI-1 connected 1280x1024+0+0 (normal left inverted right x axis y
> axis) 338mm x 270mm
> 1280x1024 60.0*+ 75.0
> 1280x960 60.0
> 1152x864 75.0
> 1024x768 75.1 70.1 60.0
> 832x624 74.6
> 800x600 72.2 75.0 60.3 56.2
> 640x480 72.8 75.0 66.7 60.0
> 720x400 70.1
> Haruka YAGNI
> hyagni at gmail.com
> xorg-driver-ati mailing list
> xorg-driver-ati at lists.x.org
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