[alsa-devel] Applied "ALSA: hda: do not override bus codec_mask in link_get()" to the asoc tree

[Mark Brown]

The patch

   ALSA: hda: do not override bus codec_mask in link_get()

has been applied to the asoc tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/sound.git for-5.6

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 43bcb1c0507858cdc95e425017dcc33f8105df39 Mon Sep 17 00:00:00 2001
From: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Date: Thu, 6 Feb 2020 22:02:21 +0200
Subject: [PATCH] ALSA: hda: do not override bus codec_mask in link_get()

snd_hdac_ext_bus_link_get() does not work correctly in case
there are multiple codecs on the bus. It unconditionally
resets the bus->codec_mask value. As per documentation in
hdaudio.h and existing use in client code, this field should
be used to store bit flag of detected codecs on the bus.

By overwriting value of the codec_mask, information on all
detected codecs is lost. No current user of hdac is impacted,
but use of bus->codec_mask is planned in future patches
for SOF.

Signed-off-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>
Reviewed-by: Ranjani Sridharan <ranjani.sridharan at linux.intel.com>
Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai at suse.de>
Link: https://lore.kernel.org/r/20200206200223.7715-1-kai.vehmanen@linux.intel.com
Signed-off-by: Mark Brown <broonie at kernel.org>
---
 sound/hda/ext/hdac_ext_controller.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/sound/hda/ext/hdac_ext_controller.c b/sound/hda/ext/hdac_ext_controller.c
index cfab60d88c92..09ff209df4a3 100644
--- a/sound/hda/ext/hdac_ext_controller.c
+++ b/sound/hda/ext/hdac_ext_controller.c
@@ -254,6 +254,7 @@ EXPORT_SYMBOL_GPL(snd_hdac_ext_bus_link_power_down_all);
 int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
 				struct hdac_ext_link *link)
 {
+	unsigned long codec_mask;
 	int ret = 0;
 
 	mutex_lock(&bus->lock);
@@ -280,9 +281,11 @@ int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
 		 *  HDA spec section 4.3 - Codec Discovery
 		 */
 		udelay(521);
-		bus->codec_mask = snd_hdac_chip_readw(bus, STATESTS);
-		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", bus->codec_mask);
-		snd_hdac_chip_writew(bus, STATESTS, bus->codec_mask);
+		codec_mask = snd_hdac_chip_readw(bus, STATESTS);
+		dev_dbg(bus->dev, "codec_mask = 0x%lx\n", codec_mask);
+		snd_hdac_chip_writew(bus, STATESTS, codec_mask);
+		if (!bus->codec_mask)
+			bus->codec_mask = codec_mask;
 	}
 
 	mutex_unlock(&bus->lock);
-- 
2.20.1