Re: Frame buffer corruptions with KVM >= 2.6.36

Avi Kivity
2010-10-14T12:11:15Z

On 10/14/2010 02:04 PM, Avi Kivity wrote:
> On 10/14/2010 09:27 AM, Jan Kiszka wrote:
>> Hi,
>>
>> I'm seeing quite frequent corruptions of the VESA frame buffer with
>> Linux guests (vga=0x317) that are starting with KVM kernel modules of
>> upcoming 2.6.36 (I'm currently running -rc7). Effects disappears when
>> downgrading to kvm-kmod-2.6.35.6. Will see if I can bisect later, but
>> maybe someone already has an idea or wants to reproduce (just run
>> something like "find /" on one text console and witch to another one -
>> text fragments will remain on the screen on every few switches).
>>
>
> Reproduces on kvm.git. I wonder what's going on.
>
> Looks like vesafb uses the bios to switch the display start, so I
> expect a problem in qemu reacting to this.
>

Hm, you said it is a kernel regression. Maybe it's an issue with dirty
bit tracking.

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