next-0519 on thinkpad x60: sound related? window manager crash

[Christoph Hellwig]

On Tue, Jun 09, 2020 at 11:31:20AM +0200, Takashi Iwai wrote:
> > > How would be a proper way to get the virtually mapped SG-buffer pages
> > > with coherent memory?  (Also allowing user-space mmap, too)
> > 
> > dma_mmap_coherent / dma_mmap_attrs for userspace.  We don't really
> > have a good way for kernel space mappings.
> 
> And that's the missing piece right now...  :-<

Can you point me to the relevant places (allocation and vmap mostly)
so that I can take a look at how to fix this mess?