linux-kernel - Re: Regression: Kernel 4.6 DisplayPort Audio

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Date:	Wed, 11 May 2016 15:09:23 +0200
From:	Takashi Iwai <tiwai@...e.de>
To:	Daniel Exner <dex@...gonslave.de>
Cc:	"Subhransu S. Prusty" <subhransu.s.prusty@...el.com>,
	Vinod Koul <vinod.koul@...el.com>, linux-kernel@...r.kernel.org
Subject: Re: Regression: Kernel 4.6 DisplayPort Audio

On Wed, 11 May 2016 14:52:22 +0200,
Daniel Exner wrote:
> 
> Hi,
> 
> Am 11.05.2016 um 10:48 schrieb Takashi Iwai:
> [..]
> 
> > If the commit above alone breaks, does the patch below change the
> > behavior?  Through a quick look at it, some ops are overridden only
> > conditionally while the older code always overwrote them.
> 
> Yes, the patch fixes it. Thanks!
> I hope its possible to include that in 4.6.

Good to hear!
FWIW, below is the proper patch I'm going to queue.


thanks,

Takashi

-- 8< --
From: Takashi Iwai <tiwai@...e.de>
Subject: [PATCH] ALSA: hda - Fix regression on ATI HDMI audio

The HDMI/DP audio output on ATI/AMD chips got broken due to the recent
restructuring of chmap.  Fortunately, Daniel Exner could bisect, and
pointed the culprit commit [739ffee97ed5: ALSA: hda - Add hdmi chmap
verb programming ops to chmap object].

This commit moved some ops from hdmi_ops to chmap_ops, and reassigned
the ops in the embedded chmap object in hdmi_spec instead.
Unfortunately, the reassignment of these ops in patch_atihdmi() were
moved into an if block that is performed only for old chips.  Thus, on
newer chips, the generic ops is still used, which doesn't work for
such ATI/AMD chips.

This patch addresses the regression, simply by moving the assignment
of chmap ops to the right place.

Fixes: 739ffee97ed5 ('ALSA: hda - Add hdmi chmap verb programming ops to chmap object')
Reported-and-tested-by: Daniel Exner <dex@...gonslave.de>
Signed-off-by: Takashi Iwai <tiwai@...e.de>
---
 sound/pci/hda/patch_hdmi.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c
index 1483f85999ec..a010d704e0e2 100644
--- a/sound/pci/hda/patch_hdmi.c
+++ b/sound/pci/hda/patch_hdmi.c
@@ -3401,6 +3401,9 @@ static int patch_atihdmi(struct hda_codec *codec)
 	spec->ops.pin_hbr_setup = atihdmi_pin_hbr_setup;
 	spec->ops.setup_stream = atihdmi_setup_stream;
 
+	spec->chmap.ops.pin_get_slot_channel = atihdmi_pin_get_slot_channel;
+	spec->chmap.ops.pin_set_slot_channel = atihdmi_pin_set_slot_channel;
+
 	if (!has_amd_full_remap_support(codec)) {
 		/* override to ATI/AMD-specific versions with pairwise mapping */
 		spec->chmap.ops.chmap_cea_alloc_validate_get_type =
@@ -3408,10 +3411,6 @@ static int patch_atihdmi(struct hda_codec *codec)
 		spec->chmap.ops.cea_alloc_to_tlv_chmap =
 				atihdmi_paired_cea_alloc_to_tlv_chmap;
 		spec->chmap.ops.chmap_validate = atihdmi_paired_chmap_validate;
-		spec->chmap.ops.pin_get_slot_channel =
-				atihdmi_pin_get_slot_channel;
-		spec->chmap.ops.pin_set_slot_channel =
-				atihdmi_pin_set_slot_channel;
 	}
 
 	/* ATI/AMD converters do not advertise all of their capabilities */
-- 
2.8.2