DDC: no ddc bus - possible BIOS bug

[Alex Deucher]

2010/12/30 屋国遥 <hyagni at gmail.com>:
> 2010/12/31 Alex Deucher <alexdeucher at gmail.com>:
>> 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
>>> <http://www.mail-archive.com/xorg-driver-ati@lists.x.org/msg16768.html>
>>> 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:
>> (as root)
>> (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
>>
>> Alex
>
> Hi, Alex.
> Thank you for your fast reply.
>

The attached patch should fix it.  I think Apple supports TV-out via a
DVI to TV dongle, so you should see a DIN connector with this patch,
but both DVI's should work correctly.

Alex

> I understood the situation.
>
> My card has just two DVI-I connectors, no TV-out.
> The attached file is vbios.rom.
> lspci -vnn result is the following (only the section of VGA controller).
>
> 02:00.0 VGA compatible controller [0300]: ATI Technologies Inc RV630
> [Radeon HD 2600XT] [1002:9588] (prog-if 00 [VGA controller])
>        Subsystem: Apple Computer Inc. Device [106b:00a6]
>        Physical Slot: 1
>        Flags: bus master, fast devsel, latency 0, IRQ 56
>        Memory at 80000000 (64-bit, prefetchable) [size=256M]
>        Memory at 90a20000 (64-bit, non-prefetchable) [size=64K]
>        I/O ports at 2000 [size=256]
>        Expansion ROM at 90a00000 [disabled] [size=128K]
>        Capabilities: <access denied>
>        Kernel driver in use: radeon
>        Kernel modules: radeon
>
>
> --
> Haruka YAGNI
> hyagni at gmail.com
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: 0001-drm-radeon-kms-add-quirk-for-Mac-Radeon-HD-2600-card.patch
Type: text/x-patch
Size: 1406 bytes
Desc: not available
URL: <http://lists.x.org/archives/xorg-driver-ati/attachments/20110103/5c8ff888/attachment.bin>