ASoC: codes: src4xxx: Avoid clang -Wsometimes-uninitialized in src4xxx_hw_params()
PATCH 1/1 ASoC: codes: src4xxx: Avoid clang -Wsometimes-uninitialized in src4xxx_hw_params()
Clang warns:
sound/soc/codecs/src4xxx.c:280:3: error: variable 'd' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
default:
^~~~~~~
sound/soc/codecs/src4xxx.c:298:59: note: uninitialized use occurs here
ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_11, d);
^
sound/soc/codecs/src4xxx.c:223:20: note: initialize the variable 'd' to silence this warning
int val, pj, jd, d;
^
= 0
sound/soc/codecs/src4xxx.c:280:3: error: variable 'jd' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
default:
^~~~~~~
sound/soc/codecs/src4xxx.c:293:59: note: uninitialized use occurs here
ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_10, jd);
^~
sound/soc/codecs/src4xxx.c:223:17: note: initialize the variable 'jd' to silence this warning
int val, pj, jd, d;
^
= 0
sound/soc/codecs/src4xxx.c:280:3: error: variable 'pj' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized]
default:
^~~~~~~
sound/soc/codecs/src4xxx.c:288:59: note: uninitialized use occurs here
ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_0F, pj);
^~
sound/soc/codecs/src4xxx.c:223:13: note: initialize the variable 'pj' to silence this warning
int val, pj, jd, d;
^
= 03 errors generated.
According to the comment in the default case, other parts of the chip are still functional without these values so just return 0 in the default case to avoid using these variables uninitialized.
--- sound/soc/codecs/src4xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
sound/soc/codecs/src4xxx.c +1 -1
@@ -283,7 +283,7 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,*/ dev_info (component->dev,"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); -break ; +return 0 ; } ret =regmap_write (src4xxx->regmap,SRC4XXX_RCV_PLL_0F , pj);if (ret <0 )
base-commit: 94f072748337424c9cf92cd018532a34db3a5516
Signature · 1 line
2.37.2
Hi Nathan,
Quoted 12 lines · Nathan Chancellor
Clang warns:
sound/soc/codecs/src4xxx.c:280:3: error: variable 'd' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized] default: ^~~~~~~ sound/soc/codecs/src4xxx.c:298:59: note: uninitialized use occurs here ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_11, d); ^ sound/soc/codecs/src4xxx.c:223:20: note: initialize the variable 'd' to silence this warning int val, pj, jd, d; ^ = 0
If you really want to get rid of these warnings, you can use this default for the variables :
pj = 0x0;
jd=0xff;
d = 0xff;
It doesn't really make sense why we would choose to initialise these variables, but if you want to silence the preprocessor, then perhaps those values. Put a message that defaults are not known nor specified in the data sheet and these values are chosen to be unlikely matches of real world values - which ensures regmap updates later from an initial unknown chip state after refresh. All a bit messy really.
Quoted 17 lines
According to the comment in the default case, other parts of the chip are still functional without these values so just return 0 in the default case to avoid using these variables uninitialized.
Reported-by kernel test robot <[email protected]>Signed-off-by Nathan Chancellor <[email protected]>--- sound/soc/codecs/src4xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)sound/soc/codecs/src4xxx.c +0
-0
sound/soc/codecs/src4xxx.c static int src4xxx_hw_params(struct snd_pcm_substream *substream, · line 286
Quoted 5 lines
sound/soc/codecs/src4xxx.c +1
-1@@ -283,7 +283,7 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,*/ dev_info (component->dev,"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); -break ; +return 0 ;
Don't return here, the rest of the chip is still functional and probably in use. Print the dev_info and continue.
Hi Matt,
Quoted 23 lines · Matt Flax
Hi Nathan,
Quoted 12 lines · Nathan Chancellor
Clang warns:
sound/soc/codecs/src4xxx.c:280:3: error: variable 'd' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized] default: ^~~~~~~ sound/soc/codecs/src4xxx.c:298:59: note: uninitialized use occurs here ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_11, d); ^ sound/soc/codecs/src4xxx.c:223:20: note: initialize the variable 'd' to silence this warning int val, pj, jd, d; ^ = 0If you really want to get rid of these warnings, you can use this default for the variables :
pj =
0x0;
jd=0xff;
Quoted 8 lines
d =
0xff;It doesn't really make sense why we would choose to initialise these variables, but if you want to silence the preprocessor, then perhaps those values. Put a message that defaults are not known nor specified in the data sheet and these values are chosen to be unlikely matches of real world values - which ensures regmap updates later from an initial unknown chip state after refresh.
Okay, I could do something like this?
sound/soc/codecs/src4xxx.c +6 -1
@@ -280,9 +280,14 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,default :/* don't error out here, * other parts of the chip are still functional +* Dummy initialize variables to avoid +* -Wsometimes-uninitialized from clang. */ dev_info (component->dev, -"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); +"Couldn't set the RCV PLL as this master clock rate is unknown. Chosen regmap values may not match real world values.\n" ); + pj =0x0 ; + jd =0xff ; + d =0xff ;break ; } ret =regmap_write (src4xxx->regmap,SRC4XXX_RCV_PLL_0F , pj);
These warnings need to be eliminated because Linus requires a clean build as much as possible [1] [2], which has been codified by CONFIG_WERROR, which is enabled by default with allmodconfig. As a result, clang allmodconfig builds are broken [3], which you might have already seen. If there is another way this could be written without potentially uninitialized variables, I am open to it.
[1]: https://lore.kernel.org/CAHk-=wg-mH-_GYpkhz_psjBWG6ZcjKnPo83fg7YMj_by+-LRTQ@mail.gmail.com/
[2]: https://lore.kernel.org/CAHk-=wi4wyvuXs0SUq-2x=XHxWmJ6jVKRD-WpE0kWgWiqVJNbg@mail.gmail.com/
[3]: https://lore.kernel.org/YwNMUlAmu%2FqCjuva@debian/
Quoted 1 line
All a bit messy really.
Indeed :/
Quoted 12 lines
Quoted 12 lines
According to the comment in the default case, other parts of the chip are still functional without these values so just return 0 in the default case to avoid using these variables uninitialized.
Reported-by kernel test robot <[email protected]>Signed-off-by Nathan Chancellor <[email protected]>--- sound/soc/codecs/src4xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
Quoted 14 lines
sound/soc/codecs/src4xxx.c static int src4xxx_hw_params(struct snd_pcm_substream *substream, · line 286
Quoted 10 lines
sound/soc/codecs/src4xxx.c +1
-1@@ -283,7 +283,7 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,*/ dev_info (component->dev,"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); -break ; +return 0 ;Don't return here, the rest of the chip is still functional and probably in use. Print the
dev_infoand continue.
I'll send a v2 tomorrow morning (for me at least) if there are no other comments.
Cheers,
Nathan
That solution looks good.
Matt
Quoted 100 lines · Nathan Chancellor
Hi Matt,
Quoted 22 lines · Matt Flax
Hi Nathan,
Quoted 12 lines · Nathan Chancellor
Clang warns:
sound/soc/codecs/src4xxx.c:280:3: error: variable 'd' is used uninitialized whenever switch default is taken [-Werror,-Wsometimes-uninitialized] default: ^~~~~~~ sound/soc/codecs/src4xxx.c:298:59: note: uninitialized use occurs here ret = regmap_write(src4xxx->regmap, SRC4XXX_RCV_PLL_11, d); ^ sound/soc/codecs/src4xxx.c:223:20: note: initialize the variable 'd' to silence this warning int val, pj, jd, d; ^ = 0If you really want to get rid of these warnings, you can use this default for the variables :
pj =
0x0;
jd=0xff;Quoted 8 lines
d =
0xff;It doesn't really make sense why we would choose to initialise these variables, but if you want to silence the preprocessor, then perhaps those values. Put a message that defaults are not known nor specified in the data sheet and these values are chosen to be unlikely matches of real world values - which ensures regmap updates later from an initial unknown chip state after refresh.
Okay, I could do something like this?
sound/soc/codecs/src4xxx.c +6
-1@@ -280,9 +280,14 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,default :/* don't error out here, * other parts of the chip are still functional +* Dummy initialize variables to avoid +* -Wsometimes-uninitialized from clang. */ dev_info (component->dev, -"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); +"Couldn't set the RCV PLL as this master clock rate is unknown. Chosen regmap values may not match real world values.\n" ); + pj =0x0 ; + jd =0xff ; + d =0xff ;break ; } ret =regmap_write (src4xxx->regmap,SRC4XXX_RCV_PLL_0F , pj);These warnings need to be eliminated because Linus requires a clean build as much as possible [1] [2], which has been codified by
CONFIG_WERROR, which is enabled by default with allmodconfig. As a result, clang allmodconfig builds are broken [3], which you might have already seen. If there is another way this could be written without potentially uninitialized variables, I am open to it.[1]: https://lore.kernel.org/CAHk-=wg-mH-_GYpkhz_psjBWG6ZcjKnPo83fg7YMj_by+-LRTQ@mail.gmail.com/
[2]: https://lore.kernel.org/CAHk-=wi4wyvuXs0SUq-2x=XHxWmJ6jVKRD-WpE0kWgWiqVJNbg@mail.gmail.com/
[3]: https://lore.kernel.org/YwNMUlAmu%2FqCjuva@debian/Quoted 1 line
All a bit messy really.
Indeed :/
Quoted 12 lines
Quoted 12 lines
According to the comment in the default case, other parts of the chip are still functional without these values so just return 0 in the default case to avoid using these variables uninitialized.
Reported-by kernel test robot <[email protected]>Signed-off-by Nathan Chancellor <[email protected]>--- sound/soc/codecs/src4xxx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)Quoted 13 lines
sound/soc/codecs/src4xxx.c static int src4xxx_hw_params(struct snd_pcm_substream *substream, · line 286
Quoted 10 lines
sound/soc/codecs/src4xxx.c +1
-1@@ -283,7 +283,7 @@ static int src4xxx_hw_params(struct snd_pcm_substream *substream,*/ dev_info (component->dev,"Couldn't set the RCV PLL as this master clock rate is unknown\n" ); -break ; +return 0 ;Don't return here, the rest of the chip is still functional and probably in use. Print the
dev_infoand continue.I'll send a v2 tomorrow morning (for me at least) if there are no other comments.
Cheers,
Nathan