Bug#660464: KMS is not working for Radeon 9250

[Jonathan Nieder <jrnieder@gmail.com>]

Hi,

Mirek Jezbera wrote:
>> On Sun, Feb 19, 2012 at 01:22:55PM +0100, Miroslav Jezbera wrote:

>>> KMS does not work in newer kernels for Radeon 9250.
[...]
>>> I am building custom kernel
>>> from debian sources, but with same config kernel built from last
>>> linux-source-3.2 does not work with X11 - only black screen is
>>> shown.
>>> Adding nomodeset kernel option helps.
>
> I have tested almost all kernels I have built. I don't know why, but nomodeset
> option is not working anymore - it does not help. Also kernel 3.2.1 runs X
> only in one case. But all 3.1 kernels and 3.3.0-rc1 kernel were working
> correctly. I have tested boot in text and start gdm manually/restart gdm
> remotely - screen is still black & I can't switch to another VT.

It is still not clear to me what is wrong ("what", not "why"), so
could you spell it out for me more?

 1. If you do not start X (I believe appending "text" to the kernel
    command line does this), does the framebuffer console work ok?
    You might need to do "modprobe radeon" to try this.

 2. Do stock Debian binary kernel images work for you?

 3. If so, how does your configuration differ from the stock one?
    A copy of your .config might be helpful.

 4. In the black screen you see, is there a cursor?  Is the backlight
    on?

 5. If I understand correctly, you are able to ssh into the machine
    even after the screen turns black.  Does "dmesg" output contain
    any information about what happened?  How about
    /var/log/Xorg.0.log?

Thanks and hope that helps,
Jonathan