Re: linux-4.6-rc4/sound/pci/ens1370.c:1551: possible bad expression ?

Re: linux-4.6-rc4/sound/pci/ens1370.c:1551: possible bad expression ?

[Takashi Iwai]

On Mon, 18 Apr 2016 18:17:58 +0200,
David Binderman wrote:
> 
> Hello there,
> 
> [linux-4.6-rc4/sound/pci/ens1370.c:1551]: (style) Expression '(X & 0xf0000)>= 0x4' is always false.
> 
> Source code is
> 
>     if ((ensoniq->ctrl & ES_1371_GPIO_OUTM)>= 4)
>         val = 1;

Thanks for the report.  It's fixed now by the patch below.


Takashi

-- 8< --
From: Takashi Iwai <tiwai@suse.de>
Subject: [PATCH] ALSA: ens1371: Fix "Line In->Rear Out Switch" control

The "Line In->Rear Out Switch" control on ens1371 driver returns a
bogus value, always true, as its check is totally broken.  Fix it to
check the proper GPIO bit mask.

Reported-by: David Binderman <dcb314@hotmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
---
 sound/pci/ens1370.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/pci/ens1370.c b/sound/pci/ens1370.c
index 0dc44ebb0032..626cd2167d29 100644
--- a/sound/pci/ens1370.c
+++ b/sound/pci/ens1370.c
@@ -1548,7 +1548,7 @@ static int snd_es1373_line_get(struct snd_kcontrol *kcontrol,
 	int val = 0;
 	
 	spin_lock_irq(&ensoniq->reg_lock);
-	if ((ensoniq->ctrl & ES_1371_GPIO_OUTM) >= 4)
+	if (ensoniq->ctrl & ES_1371_GPIO_OUT(4))
 	    	val = 1;
 	ucontrol->value.integer.value[0] = val;
 	spin_unlock_irq(&ensoniq->reg_lock);
-- 
2.8.1

Re: [alsa-devel] linux-4.6-rc4/sound/pci/ens1370.c:1551: possible bad expression ?

[Clemens Ladisch]

David Binderman wrote:
> [linux-4.6-rc4/sound/pci/ens1370.c:1551]: (style) Expression '(X & 0xf0000)>= 0x4' is always false.

What tool generated this message?

> Source code is
>
>     if ((ensoniq->ctrl & ES_1371_GPIO_OUTM)>= 4)
>         val = 1;

This message is wrong; it is certainly possible for this to be true.

However, there is a different bug: 4 must be ES_1371_GPIO_OUT(4).


Regards,
Clemens