Subject: Re: [PATCH next-20130124] Sound: pci: Fix unused variable warning in patch_sigmatel.c

From: Takashi Iwai <[email-masked]>
Date: Fri, 25 Jan 2013 11:17:56 +0100

At Fri, 25 Jan 2013 02:03:16 -0800,
Joe Perches wrote:
> 
> On Fri, 2013-01-25 at 10:09 +0100, Takashi Iwai wrote:
> > At Fri, 25 Jan 2013 00:38:06 +0200,
> > Stratos Karafotis wrote:
> > > Fix the following build warnings
> > > sound/pci/hda/patch_sigmatel.c: In function ‘stac92hd71bxx_fixup_hp’:
> > > sound/pci/hda/patch_sigmatel.c:2434:24: warning: unused variable ‘spec’ [-Wunused-variable]
> []
> > I'm going to fix the definition of snd_printd() itself for fixing this
> > kind of warnings.  We can use inline functions instead of empty macros
> > to achieve the same but without triggering compiler warnings.
> 
> It's probably better to use a macro like:
> 
> do {						\
> 	if (0)					\
> 		printk(fmt, ##__VA_ARGS__);	\
> } while (0)
> 
> to allow the compiler to avoid any argument evaluation
> while still doing fmt/arg matching.

Hm, this would work, too.
FWIW, the patch below is the patch I mentioned in the above.
I don't mind whether it's macro with if (0) or an empty inline
function...

Takashi

---
From: Takashi Iwai <[email-masked]>
Subject: [PATCH] ALSA: Make snd_printd() and snd_printdd() inline

Because currently snd_printd() and snd_printdd() macros are expanded
to empty when CONFIG_SND_DEBUG=n, a compile warning like below
appears sometimes, and we had to covert it by ugly ifdefs:
  sound/pci/hda/patch_sigmatel.c: In function ‘stac92hd71bxx_fixup_hp’:
  sound/pci/hda/patch_sigmatel.c:2434:24: warning: unused variable ‘spec’ [-Wunused-variable]

For "fixing" these issues better, this patch replaces snd_printd() and
snd_printdd() definitions with empty inline functions instead of
macros.  This should have the same effect but shut up warnings like
above.

But since we had already put ifdefs, changing to inline functions
would trigger compile errors.  So, such ifdefs is removed in this
patch.

In addition, snd_pci_quirk name field is defined only when
CONFIG_SND_DEBUG_VERBOSE is set, and the reference to it in
snd_printdd() argument triggers the build errors, too.  For avoiding
these errors, introduce a new macro snd_pci_quirk_name() that is
defined no matter how the debug option is set.

Reported-by: Stratos Karafotis <[email-masked]>
Signed-off-by: Takashi Iwai <[email-masked]>
---
 include/sound/core.h            | 12 +++++++++---
 sound/drivers/vx/vx_core.c      |  3 +--
 sound/pci/atiixp.c              |  5 +++--
 sound/pci/hda/hda_auto_parser.c |  2 --
 sound/pci/hda/hda_generic.c     |  2 --
 sound/pci/intel8x0.c            | 10 ++++++----
 sound/pci/maestro3.c            | 10 ++++++----
 sound/pci/nm256/nm256.c         |  3 ++-
 sound/pci/pcxhr/pcxhr_core.c    |  3 +--
 sound/pci/via82xx.c             |  2 +-
 sound/usb/pcm.c                 |  2 --
 11 files changed, 29 insertions(+), 25 deletions(-)

diff --git a/include/sound/core.h b/include/sound/core.h
index 93896ad..244ce5c 100644
--- a/include/sound/core.h
+++ b/include/sound/core.h
@@ -394,8 +394,11 @@ void __snd_printk(unsigned int level, const char *file, int line,
 
 #else /* !CONFIG_SND_DEBUG */
 
-#define snd_printd(fmt, args...)	do { } while (0)
-#define _snd_printd(level, fmt, args...) do { } while (0)
+__printf(1, 2)
+static inline void snd_printd(const char *format, ...) {}
+__printf(2, 3)
+static inline void _snd_printd(int level, const char *format, ...) {}
+
 #define snd_BUG()			do { } while (0)
 static inline int __snd_bug_on(int cond)
 {
@@ -416,7 +419,8 @@ static inline int __snd_bug_on(int cond)
 #define snd_printdd(format, args...) \
 	__snd_printk(2, __FILE__, __LINE__, format, ##args)
 #else
-#define snd_printdd(format, args...)	do { } while (0)
+__printf(1, 2)
+static inline void snd_printdd(const char *format, ...) {}
 #endif

@@ -454,6 +458,7 @@ struct snd_pci_quirk {
 #define SND_PCI_QUIRK_MASK(vend, mask, dev, xname, val)			\
 	{_SND_PCI_QUIRK_ID_MASK(vend, mask, dev),			\
 			.value = (val), .name = (xname)}
+#define snd_pci_quirk_name(q)	((q)->name)
 #else
 #define SND_PCI_QUIRK(vend,dev,xname,val) \
 	{_SND_PCI_QUIRK_ID(vend, dev), .value = (val)}
@@ -461,6 +466,7 @@ struct snd_pci_quirk {
 	{_SND_PCI_QUIRK_ID_MASK(vend, mask, dev), .value = (val)}
 #define SND_PCI_QUIRK_VENDOR(vend, xname, val)			\
 	{_SND_PCI_QUIRK_ID_MASK(vend, 0, 0), .value = (val)}
+#define snd_pci_quirk_name(q)	NULL
 #endif
 
 const struct snd_pci_quirk *
diff --git a/sound/drivers/vx/vx_core.c b/sound/drivers/vx/vx_core.c
index de5055a..c39961c 100644
--- a/sound/drivers/vx/vx_core.c
+++ b/sound/drivers/vx/vx_core.c
@@ -52,7 +52,6 @@ MODULE_LICENSE("GPL");
 int snd_vx_check_reg_bit(struct vx_core *chip, int reg, int mask, int bit, int time)
 {
 	unsigned long end_time = jiffies + (time * HZ + 999) / 1000;
-#ifdef CONFIG_SND_DEBUG
 	static char *reg_names[VX_REG_MAX] = {
 		"ICR", "CVR", "ISR", "IVR", "RXH", "RXM", "RXL",
 		"DMA", "CDSP", "RFREQ", "RUER/V2", "DATA", "MEMIRQ",
@@ -60,7 +59,7 @@ int snd_vx_check_reg_bit(struct vx_core *chip, int reg, int mask, int bit, int t
 		"MIC3", "INTCSR", "CNTRL", "GPIOC",
 		"LOFREQ", "HIFREQ", "CSUER", "RUER"
 	};
-#endif
+
 	do {
 		if ((snd_vx_inb(chip, reg) & mask) == bit)
 			return 0;
diff --git a/sound/pci/atiixp.c b/sound/pci/atiixp.c
index a677431..6e78c67 100644
--- a/sound/pci/atiixp.c
+++ b/sound/pci/atiixp.c
@@ -567,8 +567,9 @@ static int ac97_probing_bugs(struct pci_dev *pci)
 
 	q = snd_pci_quirk_lookup(pci, atiixp_quirks);
 	if (q) {
-		snd_printdd(KERN_INFO "Atiixp quirk for %s.  "
-			    "Forcing codec %d\n", q->name, q->value);
+		snd_printdd(KERN_INFO
+			    "Atiixp quirk for %s.  Forcing codec %d\n",
+			    snd_pci_quirk_name(q), q->value);
 		return q->value;
 	}
 	/* this hardware doesn't need workarounds.  Probe for codec */
diff --git a/sound/pci/hda/hda_auto_parser.c b/sound/pci/hda/hda_auto_parser.c
index 96a05c4..a3ea76a 100644
--- a/sound/pci/hda/hda_auto_parser.c
+++ b/sound/pci/hda/hda_auto_parser.c
@@ -698,9 +698,7 @@ static void set_pin_targets(struct hda_codec *codec,
 
 static void apply_fixup(struct hda_codec *codec, int id, int action, int depth)
 {
-#ifdef CONFIG_SND_DEBUG_VERBOSE
 	const char *modelname = codec->fixup_name;
-#endif
 
 	while (id >= 0) {
 		const struct hda_fixup *fix = codec->fixup_list + id;
diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index 19d014a..c4ba306 100644
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -1579,9 +1579,7 @@ static void debug_show_configs(struct hda_codec *codec,
 			       struct auto_pin_cfg *cfg)
 {
 	struct hda_gen_spec *spec = codec->spec;
-#ifdef CONFIG_SND_DEBUG_VERBOSE
 	static const char * const lo_type[3] = { "LO", "SP", "HP" };
-#endif
 	int i;
 
 	debug_badness("multi_outs = %x/%x/%x/%x : %x/%x/%x/%x (type %s)\n",
diff --git a/sound/pci/intel8x0.c b/sound/pci/intel8x0.c
index 3b9be75..b8fe405 100644
--- a/sound/pci/intel8x0.c
+++ b/sound/pci/intel8x0.c
@@ -3266,11 +3266,13 @@ static int check_default_spdif_aclink(struct pci_dev *pci)
 	w = snd_pci_quirk_lookup(pci, spdif_aclink_defaults);
 	if (w) {
 		if (w->value)
-			snd_printdd(KERN_INFO "intel8x0: Using SPDIF over "
-				    "AC-Link for %s\n", w->name);
+			snd_printdd(KERN_INFO
+				    "intel8x0: Using SPDIF over AC-Link for %s\n",
+				    snd_pci_quirk_name(w));
 		else
-			snd_printdd(KERN_INFO "intel8x0: Using integrated "
-				    "SPDIF DMA for %s\n", w->name);
+			snd_printdd(KERN_INFO
+				    "intel8x0: Using integrated SPDIF DMA for %s\n",
+				    snd_pci_quirk_name(w));
 		return w->value;
 	}
 	return 0;
diff --git a/sound/pci/maestro3.c b/sound/pci/maestro3.c
index 9387533..c76ac14 100644
--- a/sound/pci/maestro3.c
+++ b/sound/pci/maestro3.c
@@ -2586,8 +2586,9 @@ snd_m3_create(struct snd_card *card, struct pci_dev *pci,
 	else {
 		quirk = snd_pci_quirk_lookup(pci, m3_amp_quirk_list);
 		if (quirk) {
-			snd_printdd(KERN_INFO "maestro3: set amp-gpio "
-				    "for '%s'\n", quirk->name);
+			snd_printdd(KERN_INFO
+				    "maestro3: set amp-gpio for '%s'\n",
+				    snd_pci_quirk_name(quirk));
 			chip->amp_gpio = quirk->value;
 		} else if (chip->allegro_flag)
 			chip->amp_gpio = GPO_EXT_AMP_ALLEGRO;
@@ -2597,8 +2598,9 @@ snd_m3_create(struct snd_card *card, struct pci_dev *pci,
 
 	quirk = snd_pci_quirk_lookup(pci, m3_irda_quirk_list);
 	if (quirk) {
-		snd_printdd(KERN_INFO "maestro3: enabled irda workaround "
-			    "for '%s'\n", quirk->name);
+		snd_printdd(KERN_INFO
+			    "maestro3: enabled irda workaround for '%s'\n",
+			    snd_pci_quirk_name(quirk));
 		chip->irda_workaround = 1;
 	}
 	quirk = snd_pci_quirk_lookup(pci, m3_hv_quirk_list);
diff --git a/sound/pci/nm256/nm256.c b/sound/pci/nm256/nm256.c
index 563a193..6febedb 100644
--- a/sound/pci/nm256/nm256.c
+++ b/sound/pci/nm256/nm256.c
@@ -1660,7 +1660,8 @@ static int snd_nm256_probe(struct pci_dev *pci,
 
 	q = snd_pci_quirk_lookup(pci, nm256_quirks);
 	if (q) {
-		snd_printdd(KERN_INFO "nm256: Enabled quirk for %s.\n", q->name);
+		snd_printdd(KERN_INFO "nm256: Enabled quirk for %s.\n",
+			    snd_pci_quirk_name(q));
 		switch (q->value) {
 		case NM_BLACKLISTED:
 			printk(KERN_INFO "nm256: The device is blacklisted. "
diff --git a/sound/pci/pcxhr/pcxhr_core.c b/sound/pci/pcxhr/pcxhr_core.c
index b33db1e..37b431b 100644
--- a/sound/pci/pcxhr/pcxhr_core.c
+++ b/sound/pci/pcxhr/pcxhr_core.c
@@ -1012,13 +1012,12 @@ static int pcxhr_handle_async_err(struct pcxhr_mgr *mgr, u32 err,
 				  enum pcxhr_async_err_src err_src, int pipe,
 				  int is_capture)
 {
-#ifdef CONFIG_SND_DEBUG_VERBOSE
 	static char* err_src_name[] = {
 		[PCXHR_ERR_PIPE]	= "Pipe",
 		[PCXHR_ERR_STREAM]	= "Stream",
 		[PCXHR_ERR_AUDIO]	= "Audio"
 	};
-#endif
+
 	if (err & 0xfff)
 		err &= 0xfff;
 	else
diff --git a/sound/pci/via82xx.c b/sound/pci/via82xx.c
index 6442f61..d756a35 100644
--- a/sound/pci/via82xx.c
+++ b/sound/pci/via82xx.c
@@ -2517,7 +2517,7 @@ static int check_dxs_list(struct pci_dev *pci, int revision)
 	w = snd_pci_quirk_lookup(pci, dxs_whitelist);
 	if (w) {
 		snd_printdd(KERN_INFO "via82xx: DXS white list for %s found\n",
-			    w->name);
+			    snd_pci_quirk_name(w));
 		return w->value;
 	}
 
diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index b839b60..81f70a7 100644
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -1179,9 +1179,7 @@ static void retire_capture_urb(struct snd_usb_substream *subs,
 		if (!subs->txfr_quirk)
 			bytes = frames * stride;
 		if (bytes % (runtime->sample_bits >> 3) != 0) {
-#ifdef CONFIG_SND_DEBUG_VERBOSE
 			int oldbytes = bytes;
-#endif
 			bytes = frames * stride;
 			snd_printdd(KERN_ERR "Corrected urb data len. %d->%d\n",
 							oldbytes, bytes);
-- 
1.8.1.1