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Date:   Sun, 07 Jun 2020 22:13:42 -0400
From:   "Alex Xu (Hello71)" <alex_y_xu@yahoo.ca>
Subject: Re: 82fef0ad811f "x86/mm: unencrypted non-blocking DMA allocations
 use coherent pools" was Re: next-0519 on thinkpad x60: sound related? window
 manager crash
To:     David Rientjes <rientjes@google.com>
Cc:     alsa-devel@alsa-project.org, bp@alien8.de, hch@infradead.org,
        hch@lst.de, hpa@zytor.com, linux-kernel@vger.kernel.org,
        mingo@redhat.com, Pavel Machek <pavel@ucw.cz>, perex@perex.cz,
        tglx@linutronix.de, tiwai@suse.com, x86@kernel.org
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Excerpts from David Rientjes's message of June 7, 2020 8:57 pm:
> Thanks for trying it out, Alex.  Would you mind sending your .config and=20
> command line?  I assume either mem_encrypt=3Don or=20
> CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT is enabled.
>=20
> Could you also give this a try?
>=20
> diff --git a/kernel/dma/direct.c b/kernel/dma/direct.c
> --- a/kernel/dma/direct.c
> +++ b/kernel/dma/direct.c
> @@ -99,10 +99,11 @@ static inline bool dma_should_alloc_from_pool(struct =
device *dev, gfp_t gfp,
>  static inline bool dma_should_free_from_pool(struct device *dev,
>  					     unsigned long attrs)
>  {
> -	if (IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
> +	if (!IS_ENABLED(CONFIG_DMA_COHERENT_POOL))
> +		return false;
> +	if (force_dma_unencrypted(dev))
>  		return true;
> -	if ((attrs & DMA_ATTR_NO_KERNEL_MAPPING) &&
> -	    !force_dma_unencrypted(dev))
> +	if (attrs & DMA_ATTR_NO_KERNEL_MAPPING)
>  		return false;
>  	if (IS_ENABLED(CONFIG_DMA_DIRECT_REMAP))
>  		return true;
>=20

This patch doesn't work for me either. It has since occurred to me that=20
while I do have CONFIG_AMD_MEM_ENCYRPT=3Dy, I have=20
CONFIG_AMD_MEM_ENCRYPT_ACTIVE_BY_DEFAULT=3Dn, because it was broken with=20
amdgpu (unfortunately a downgrade from radeon in this respect). Tried it=20
again just now and it looks like it's now able to enable KMS, but all it=20
displays is serious-looking errors.

Sorry for not mentioning that earlier. I'll send you my .config and=20
command line off-list.

Thanks,
Alex.