[PATCH] ALSA: intel_hdmi: Fix reference to PCM buffer address

[PATCH] ALSA: intel_hdmi: Fix reference to PCM buffer address

[Zhen Ni]

PCM buffers might be allocated dynamically when the buffer
preallocation failed or a larger buffer is requested, and it's not
guaranteed that substream->dma_buffer points to the actually used
buffer.  The driver needs to refer to substream->runtime->dma_addr
instead for the buffer address.

Signed-off-by: Zhen Ni <nizhen@uniontech.com>
---
 sound/x86/intel_hdmi_audio.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c
index 1c94eaff1931..4a3ff6468aa7 100644
--- a/sound/x86/intel_hdmi_audio.c
+++ b/sound/x86/intel_hdmi_audio.c
@@ -1261,7 +1261,7 @@ static int had_pcm_mmap(struct snd_pcm_substream *substream,
 {
 	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
 	return remap_pfn_range(vma, vma->vm_start,
-			substream->dma_buffer.addr >> PAGE_SHIFT,
+			substream->runtime->dma_addr >> PAGE_SHIFT,
 			vma->vm_end - vma->vm_start, vma->vm_page_prot);
 }
 
-- 
2.20.1

Re: [PATCH] ALSA: intel_hdmi: Fix reference to PCM buffer address

[Takashi Iwai]

On Wed, 02 Mar 2022 08:42:41 +0100,
Zhen Ni wrote:
> 
> PCM buffers might be allocated dynamically when the buffer
> preallocation failed or a larger buffer is requested, and it's not
> guaranteed that substream->dma_buffer points to the actually used
> buffer.  The driver needs to refer to substream->runtime->dma_addr
> instead for the buffer address.
> 
> Signed-off-by: Zhen Ni <nizhen@uniontech.com>

Thanks, applied now with Cc-to-stable.

I guess the had_pcm_mmap() can be dropped completely and replaced with
the standard mmap helper, as what we really want is rather wc.
But it can be done for 5.18.


Takashi