Re: ttm dma allocator issue ?

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Mon, Dec 12, 2011 at 12:37:43PM -0500, Konrad Rzeszutek Wilk wrote:
> > > Any ideas ?
> > 
> > The only way to do that would be to modify the 'struct dma_page' vaddr and dma
> > variables from what they had in __ttm_dma_alloc_page. But I am not seeing any
> > willfull modifications. We do pass in to dma_free_coherent the _same_ values!
> > 
> > 
> > Hm, it might be worth adding in the 'struct dma_page' a 'virt_to_phys' value
> > (which is what the DMA debug API uses to check), and see we get inconsitent
> > values _before_ we call the DMA debug API. This is rather to double check
> > the DMA API debug API. I am going to try something like this (not compile tested at all):
> 
> This one is compile tested :-)
> 
> diff --git a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> index 6678abc..659b0ee 100644
> --- a/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> +++ b/drivers/gpu/drm/ttm/ttm_page_alloc_dma.c
> @@ -32,7 +32,7 @@
>   * - Tracks whether the page is UC, WB or cached (and reverts to WB
>   *   when freed).
>   */
> -

And I think if you cherry-pick git commit 91ec37cc1015220965e39bf342fb846810d19e79

Author: Thomas Jarosch <thomas.jarosch@intra2net.com>
Date:   Thu Nov 17 20:31:02 2011 +0100

    Fix comparison using wrong pointer variable in dma debug code

which fixes the DMA debug API code, the error you are getting will go away.