Re: Faulty MTRR setups in Toshiba laptops crash video drivers

[Robert Hancock]

On 11/02/2009 10:28 AM, Mehmet Giritli wrote:
> Hello all,
>
> On some laptops using ATI 3650HD radeon chipsets and 4GB ram (and may be
> others as well), it is impossible to start any xserver due to (faulty?)
> mtrr setups on the machine. The computer locks up or just gives an
> unresponsive black screen. There are various drivers for radeon cards
> and the crash occurs in all of these drivers in the very same way!
>
> This bug seems to occur mostly on Toshiba laptops with ATI graphic
> cards. For some people, CONFIG_MTRR_SANITIZER seemed to cure the issue
> but made no difference for many others like me.
>
> RadeonHD people seem to have problems in understanding the nature of
> this bug. Please have a look at the threads:
>
> http://lists.opensuse.org/radeonhd/2009-05/msg00040.html
>
> and,
>
> http://bugs.freedesktop.org/show_bug.cgi?id=20645
>
> for problem reports and dev responses. RadeonHD devs suggest that some
> laptops have weird mtrr setups and this must be fixed in the kernel code
> and not the driver code.

Unfortunately I don't see enough details to be able to tell what lead 
them to this conclusion. Can you post the output of:

lspci -vv
cat /proc/mtrr

> Currently, the only way that could make the driver work is to reduce the
> 4GB ram to 2GB.
>
> dmesg from my affected machine when it has 4GB ram installed can be
> found here:
>
> http://bugzilla.kernel.org/attachment.cgi?id=22856
>
> Also, look at the report here:
>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/341681
>
> in order to see how many people are being affected by this bug!
>
> Kind Regards,
> M. Giritli

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