[5.14 regression] "ALSA: core: Add continuous and vmalloc mmap ops" breaks Intel SST audio

[Takashi Iwai]

On Fri, 30 Jul 2021 22:04:00 +0200,
Hans de Goede wrote:
> 
> Hi All;,
> 
> As discussed in the "5.14 regression, Intel SST (BYT) audio no longer works" thread,
> audio on X86 devices using the Intel SST driver no longer works with 5.14.
> 
> After poking at this for a while I've found the culprit:
> 30b7ba6972d5 ("ALSA: core: Add continuous and vmalloc mmap ops")
> 
> If I revert that single commit then everything works fine again with 5.14.

Does the patch below fix the problem?


thanks,

Takashi

---
--- a/sound/core/memalloc.c
+++ b/sound/core/memalloc.c
@@ -215,7 +215,7 @@ static int snd_dma_continuous_mmap(struct snd_dma_buffer *dmab,
 				   struct vm_area_struct *area)
 {
 	return remap_pfn_range(area, area->vm_start,
-			       dmab->addr >> PAGE_SHIFT,
+			       page_to_pfn(virt_to_page(dmab->area)),
 			       area->vm_end - area->vm_start,
 			       area->vm_page_prot);
 }