On Thu, Apr 19, 2018 at 08:19:09AM +0200, Takashi Iwai wrote:
> commit 9e7f06c8beee304ee21b791653fefcd713f48b9a upstream.
>
> The code refactoring by commit 0176adb00406 ("swiotlb: refactor coherent
> buffer allocation") made swiotlb_alloc_buffer almost always failing due
> to a thinko: namely, the function evaluates the dma_coherent_ok call
> incorrectly and dealing as if it's invalid. This ends up with weird
> errors like iwlwifi probe failure or amdgpu screen flickering.
>
> This patch corrects the logic error.
>
> Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1088658
> Bugzilla: https://bugzilla.suse.com/show_bug.cgi?id=1088902
> Fixes: 0176adb00406 ("swiotlb: refactor coherent buffer allocation")
> Cc: <stable@xxxxxxxxxxxxxxx> # v4.16+
> Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
> Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> ---
>
> Greg, this is a commit that felt out in the previous round due to
> cherry-pick error. Resent with a context fix.
Now queued up, thanks.
greg k-h