Patch "ALSA: pcm: Use dma_bytes as size parameter in dma_mmap_coherent()" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

ALSA: pcm: Use dma_bytes as size parameter in dma_mmap_coherent()

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
alsa-pcm-use-dma_bytes-as-size-parameter-in-dma_mmap_coherent.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefan Roese <[email protected]>
Date: Mon, 26 Mar 2018 16:10:21 +0200
Subject: ALSA: pcm: Use dma_bytes as size parameter in dma_mmap_coherent()

From: Stefan Roese <[email protected]>

commit 9066ae7ff5d89c0b5daa271e2d573540097a94fa upstream.

When trying to use the driver (e.g. aplay *.wav), the 4MiB DMA buffer will get mmapp'ed in 16KiB chunks. But this fails with the 2nd 16KiB area, as the page offset is outside of the VMA range (size), which is currently used as size parameter in snd_pcm_lib_default_mmap(). By using the DMA buffer size (dma_bytes) instead, the complete DMA buffer can be mmapp'ed and the issue is fixed.

This issue was detected on an ARM platform (TI AM57xx) using the RME HDSP MADI PCIe soundcard.

---
 sound/core/pcm_native.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -3422,7 +3422,7 @@ int snd_pcm_lib_default_mmap(struct snd_
 					 area,
 					 substream->runtime->dma_area,
 					 substream->runtime->dma_addr,
-					 area->vm_end - area->vm_start);
+					 substream->runtime->dma_bytes);
 #endif /* CONFIG_X86 */
 	/* mmap with fault handler */
 	area->vm_ops = &snd_pcm_vm_ops_data_fault;

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/alsa-pcm-use-dma_bytes-as-size-parameter-in-dma_mmap_coherent.patch