[patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[Dan Carpenter]

I don't think this works as intended.  '|' higher precedence than ?: so
the bitwize OR "0 | (val & STR_MOST)" is a no-op.

I have re-written it to be more clear.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
---
I don't have a way to test this.

diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
index 50169bc..7266020 100644
--- a/sound/pci/es1968.c
+++ b/sound/pci/es1968.c
@@ -2581,9 +2581,14 @@ static u8 snd_es1968_tea575x_get_pins(struct snd_tea575x *tea)
 	struct es1968 *chip = tea->private_data;
 	unsigned long io = chip->io_port + GPIO_DATA;
 	u16 val = inw(io);
-
-	return  (val & STR_DATA) ? TEA575X_DATA : 0 |
-		(val & STR_MOST) ? TEA575X_MOST : 0;
+	u8 ret;
+
+	ret = 0;
+	if (val & STR_DATA)
+		ret |= TEA575X_DATA;
+	if (val & STR_MOST)
+		ret |= TEA575X_MOST;
+	return ret;
 }
 
 static void snd_es1968_tea575x_set_direction(struct snd_tea575x *tea, bool output)

Re: [patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[Takashi Iwai]

At Tue, 13 Nov 2012 10:44:54 +0300,
Dan Carpenter wrote:
> 
> I don't think this works as intended.  '|' higher precedence than ?: so
> the bitwize OR "0 | (val & STR_MOST)" is a no-op.
> 
> I have re-written it to be more clear.
> 
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>

Thanks, applied now.


Takashi

> ---
> I don't have a way to test this.
> 
> diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
> index 50169bc..7266020 100644
> --- a/sound/pci/es1968.c
> +++ b/sound/pci/es1968.c
> @@ -2581,9 +2581,14 @@ static u8 snd_es1968_tea575x_get_pins(struct snd_tea575x *tea)
>  	struct es1968 *chip = tea->private_data;
>  	unsigned long io = chip->io_port + GPIO_DATA;
>  	u16 val = inw(io);
> -
> -	return  (val & STR_DATA) ? TEA575X_DATA : 0 |
> -		(val & STR_MOST) ? TEA575X_MOST : 0;
> +	u8 ret;
> +
> +	ret = 0;
> +	if (val & STR_DATA)
> +		ret |= TEA575X_DATA;
> +	if (val & STR_MOST)
> +		ret |= TEA575X_MOST;
> +	return ret;
>  }
>  
>  static void snd_es1968_tea575x_set_direction(struct snd_tea575x *tea, bool output)
> 

Re: [patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[Joe Perches]

On Tue, 2012-11-13 at 10:44 +0300, Dan Carpenter wrote:
> I don't think this works as intended.  '|' higher precedence than ?: so
> the bitwize OR "0 | (val & STR_MOST)" is a no-op.
> 
> I have re-written it to be more clear.
[]
> diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
[]
> @@ -2581,9 +2581,14 @@ static u8 snd_es1968_tea575x_get_pins(struct snd_tea575x *tea)
>  	struct es1968 *chip = tea->private_data;
>  	unsigned long io = chip->io_port + GPIO_DATA;
>  	u16 val = inw(io);
> -
> -	return  (val & STR_DATA) ? TEA575X_DATA : 0 |
> -		(val & STR_MOST) ? TEA575X_MOST : 0;
> +	u8 ret;
> +
> +	ret = 0;
> +	if (val & STR_DATA)
> +		ret |= TEA575X_DATA;
> +	if (val & STR_MOST)
> +		ret |= TEA575X_MOST;
> +	return ret;

Cute.  smatch I presume?  Tools are useful.

Moving the close parentheses is a pretty common style too

	return  (val & STR_DATA ? TEA575X_DATA : 0) |
		(val & STR_MOST ? TEA575X_MOST : 0);

Re: [patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[Dan Carpenter]

On Tue, Nov 13, 2012 at 12:03:10AM -0800, Joe Perches wrote:
> On Tue, 2012-11-13 at 10:44 +0300, Dan Carpenter wrote:
> > I don't think this works as intended.  '|' higher precedence than ?: so
> > the bitwize OR "0 | (val & STR_MOST)" is a no-op.
> > 
> > I have re-written it to be more clear.
> []
> > diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
> []
> > @@ -2581,9 +2581,14 @@ static u8 snd_es1968_tea575x_get_pins(struct snd_tea575x *tea)
> >  	struct es1968 *chip = tea->private_data;
> >  	unsigned long io = chip->io_port + GPIO_DATA;
> >  	u16 val = inw(io);
> > -
> > -	return  (val & STR_DATA) ? TEA575X_DATA : 0 |
> > -		(val & STR_MOST) ? TEA575X_MOST : 0;
> > +	u8 ret;
> > +
> > +	ret = 0;
> > +	if (val & STR_DATA)
> > +		ret |= TEA575X_DATA;
> > +	if (val & STR_MOST)
> > +		ret |= TEA575X_MOST;
> > +	return ret;
> 
> Cute.  smatch I presume?  Tools are useful.

Yep.  This is a smatch thing.

> 
> Moving the close parentheses is a pretty common style too
> 
> 	return  (val & STR_DATA ? TEA575X_DATA : 0) |
> 		(val & STR_MOST ? TEA575X_MOST : 0);

That would work as well, of course.  I don't have a strong
preference either way.

regards,
dan carpenter

Re: [patch] ALSA: es1968: precedence bug in snd_es1968_tea575x_get_pins()

[Ondrej Zary]

On Tuesday 13 November 2012 08:44:54 Dan Carpenter wrote:
> I don't think this works as intended.  '|' higher precedence than ?: so
> the bitwize OR "0 | (val & STR_MOST)" is a no-op.
>
> I have re-written it to be more clear.
>
> Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
> ---
> I don't have a way to test this.

Thanks for the patch. I tested it and it works.

The same way as without the patch...weird. DATA pin reading works because 
that's required for the chip detection. Stereo indication (MOST pin) works 
too.

>
> diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
> index 50169bc..7266020 100644
> --- a/sound/pci/es1968.c
> +++ b/sound/pci/es1968.c
> @@ -2581,9 +2581,14 @@ static u8 snd_es1968_tea575x_get_pins(struct
> snd_tea575x *tea) struct es1968 *chip = tea->private_data;
>  	unsigned long io = chip->io_port + GPIO_DATA;
>  	u16 val = inw(io);
> -
> -	return  (val & STR_DATA) ? TEA575X_DATA : 0 |
> -		(val & STR_MOST) ? TEA575X_MOST : 0;
> +	u8 ret;
> +
> +	ret = 0;
> +	if (val & STR_DATA)
> +		ret |= TEA575X_DATA;
> +	if (val & STR_MOST)
> +		ret |= TEA575X_MOST;
> +	return ret;
>  }
>
>  static void snd_es1968_tea575x_set_direction(struct snd_tea575x *tea, bool
> output) --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at  http://www.tux.org/lkml/


-- 
Ondrej Zary