Failed to open DRM device

[Alex Deucher]

On Mon, Oct 25, 2010 at 11:43 AM, Zhang Weiwu <zhangweiwu at realss.com> wrote:
>  On 10/25/2010 11:32 PM, Alex Deucher wrote:
>> The drm is not able to access the rom on your secondary card so it's
>> not able to initialize it.  From your dmesg:
>> [   16.705425] radeon 0000:02:00.0: Invalid ROM contents
>> [   16.705469] radeon 0000:02:00.0: Invalid ROM contents
>> [   16.705480] [drm:radeon_get_bios] *ERROR* Unable to locate a BIOS ROM
>>
> I am sorry being newbie in a geeky list. The big difference of newbie
> and geek is, newbie usually carry two questions (as I wrote:)
>> What do you think is my problem and how to fix it so X always starts on
>> boot?
> So the first question is what is the problem, second being how to fix it.
>
> While geek only have one question "what is the problem" and they can fix
> it themselves if they know what problem is it.
>
> So thanks for helping answer the first question... :)
>
> So, much to go against the wisdom of asking question the right way, may
> I also ask the second question "what should I do now?"
>
> Since I don't need the second video card in Linux, but only need it in
> dual-booted Windows, can I simply add a parameter on kernel start-up to
> ignore probing the second video card? I'd be glad be told the parameter
> directly or where to look for the answer.

You can specify the busid of the card you want X to start on in the
device section of your xorg.conf:
e.g.,

BusID "PCI:2:0:0"

Alex