Patch "ASoC: skl: Fix kernel warning due to zero NHTL entry" 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

ASoC: skl: Fix kernel warning due to zero NHTL entry

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:
asoc-skl-fix-kernel-warning-due-to-zero-nhtl-entry.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: Takashi Iwai <[email protected]>
Date: Wed, 3 Jan 2018 16:38:46 +0100
Subject: ASoC: skl: Fix kernel warning due to zero NHTL entry

From: Takashi Iwai <[email protected]>

commit 20a1ea2222e7cbf96e9bf8579362e971491e6aea upstream.

I got the following kernel warning when loading snd-soc-skl module on Dell Latitude 7270 laptop:
memremap attempted on mixed range 0x0000000000000000 size: 0x0

 WARNING: CPU: 0 PID: 484 at kernel/memremap.c:98 memremap+0x8a/0x180
 Call Trace:
  skl_nhlt_init+0x82/0xf0 [snd_soc_skl]
  skl_probe+0x2ee/0x7c0 [snd_soc_skl]
  ....

It seems that the machine doesn't support the SKL DSP gives the empty NHLT entry, and it triggers the warning. For avoiding it, let do the zero check before calling memremap().

---
 sound/soc/intel/skylake/skl-nhlt.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

@@ -43,7 +43,8 @@ struct nhlt_acpi_table *skl_nhlt_init(st
 	obj = acpi_evaluate_dsm(handle, &osc_guid, 1, 1, NULL);
 	if (obj && obj->type == ACPI_TYPE_BUFFER) {
 		nhlt_ptr = (struct nhlt_resource_desc  *)obj->buffer.pointer;
-		nhlt_table = (struct nhlt_acpi_table *)
+		if (nhlt_ptr->length)
+			nhlt_table = (struct nhlt_acpi_table *)
 				memremap(nhlt_ptr->min_addr, nhlt_ptr->length,
 				MEMREMAP_WB);
 		ACPI_FREE(obj);

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

queue-4.15/asoc-skl-fix-kernel-warning-due-to-zero-nhtl-entry.patch