On 01/07/2016 08:44 AM, Takashi Iwai wrote:

On Wed, 06 Jan 2016 22:05:35 +0100,
Shuah Khan wrote:

quoted

diff --git a/sound/usb/Makefile b/sound/usb/Makefile
index 2d2d122..665fdd9 100644
--- a/sound/usb/Makefile
+++ b/sound/usb/Makefile

@@ -2,6 +2,18 @@
 # Makefile for ALSA
 #
 
+# Media Controller
+ifeq ($(CONFIG_MEDIA_CONTROLLER),y)
+  ifeq ($(CONFIG_MEDIA_SUPPORT),y)
+        KBUILD_CFLAGS += -DUSE_MEDIA_CONTROLLER
+  endif
+  ifeq ($(CONFIG_MEDIA_SUPPORT_MODULE),y)
+    ifeq ($(MODULE),y)
+          KBUILD_CFLAGS += -DUSE_MEDIA_CONTROLLER
+    endif
+  endif
+endif

Can't we define this rather via Kconfig?
Doing this in Makefile is way too tricky, and it's unclear to users
whether MC is actually enabled or not.

Yeah doing this in Makefile is a bit tricky
and can lead to confusion.

I can't think of any specific reason why I added
this check to the Makefile instead of Kconfig.
Looks like I added this in my second version
of the patch series several months ago and didn't
revisit. I will add this to Kconfig.

quoted

diff --git a/sound/usb/media.c b/sound/usb/media.c
new file mode 100644
index 0000000..747a66a
--- /dev/null
+++ b/sound/usb/media.c

@@ -0,0 +1,214 @@
+/*
+ * media.c - Media Controller specific ALSA driver code
+ *
+ * Copyright (c) 2015 Shuah Khan <shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org>
+ * Copyright (c) 2015 Samsung Electronics Co., Ltd.
+ *
+ * This file is released under the GPLv2.
+ */
+
+/*
+ * This file adds Media Controller support to ALSA driver
+ * to use the Media Controller API to share tuner with DVB
+ * and V4L2 drivers that control media device. Media device
+ * is created based on existing quirks framework. Using this
+ * approach, the media controller API usage can be added for
+ * a specific device.
+*/
+
+#include <linux/init.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+#include <linux/usb.h>
+#include <linux/moduleparam.h>
+#include <linux/mutex.h>
+#include <linux/usb/audio.h>
+#include <linux/usb/audio-v2.h>
+#include <linux/module.h>
+
+#include <sound/control.h>
+#include <sound/core.h>
+#include <sound/info.h>
+#include <sound/pcm.h>
+#include <sound/pcm_params.h>
+#include <sound/initval.h>
+
+#include "usbaudio.h"
+#include "card.h"
+#include "midi.h"
+#include "mixer.h"
+#include "proc.h"
+#include "quirks.h"
+#include "endpoint.h"
+#include "helper.h"
+#include "debug.h"
+#include "pcm.h"
+#include "format.h"
+#include "power.h"
+#include "stream.h"
+#include "media.h"

I believe we can get rid of many include files just for MC support...

quoted

+#ifdef USE_MEDIA_CONTROLLER

This ifdef can be removed once if we build this object file
conditionally in Makefile.

Right.

quoted

@@ -1232,7 +1244,10 @@ static int snd_usb_pcm_open(struct snd_pcm_substream *substream, int direction)
 	subs->dsd_dop.channel = 0;
 	subs->dsd_dop.marker = 1;
 
-	return setup_hw_info(runtime, subs);
+	ret = setup_hw_info(runtime, subs);
+	if (ret == 0)
+		ret = media_stream_init(subs, as->pcm, direction);

Need to call snd_usb_autosuspend() in the error path.

I will add it.

quoted

--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c

@@ -544,13 +545,19 @@ int snd_usb_create_quirk(struct snd_usb_audio *chip,
 		[QUIRK_AUDIO_ALIGN_TRANSFER] = create_align_transfer_quirk,
 		[QUIRK_AUDIO_STANDARD_MIXER] = create_standard_mixer_quirk,
 	};
+	int ret;
 
+	if (quirk->media_device) {
+		/* don't want to fail when media_device_create() fails */
+		media_device_create(chip, iface);
+	}

So far, so good...

quoted

 	if (quirk->type < QUIRK_TYPE_COUNT) {
-		return quirk_funcs[quirk->type](chip, iface, driver, quirk);
+		ret = quirk_funcs[quirk->type](chip, iface, driver, quirk);
 	} else {
 		usb_audio_err(chip, "invalid quirk type %d\n", quirk->type);
 		return -ENXIO;
 	}
+	return ret;

Any reason to change this?

Thanks for catching this. I think I might have
added some debug code to print ret value and
missed it when I cleaned up the debug code.
I will fix it.

thanks,
-- Shuah

-- 
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh-JPH+aEBZ4P+UEJcrhfAQsw@public.gmane.org | (970) 217-8978