2015-02-08 20:55:42

by Luis de Bethencourt

Subject: [PATCH] media: cxd2099: move pre-init values out of init()

Improve code readability by moving out all pre-init values from the init
function.

Signed-off-by: Luis de Bethencourt <[email protected]>
---
drivers/staging/media/cxd2099/cxd2099.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/staging/media/cxd2099/cxd2099.c b/drivers/staging/media/cxd2099/cxd2099.c
index 657ea48..bafe36f 100644
--- a/drivers/staging/media/cxd2099/cxd2099.c
+++ b/drivers/staging/media/cxd2099/cxd2099.c
@@ -300,7 +300,6 @@ static int init(struct cxd *ci)
int status;

mutex_lock(&ci->lock);
- ci->mode = -1;
do {
status = write_reg(ci, 0x00, 0x00);
if (status < 0)
@@ -420,7 +419,6 @@ static int init(struct cxd *ci)
status = write_regm(ci, 0x09, 0x08, 0x08);
if (status < 0)
break;
- ci->cammode = -1;
cam_mode(ci, 0);
} while (0);
mutex_unlock(&ci->lock);
@@ -711,6 +709,8 @@ struct dvb_ca_en50221 *cxd2099_attach(struct cxd2099_cfg *cfg,

ci->en = en_templ;
ci->en.data = ci;
+ ci->mode = -1;
+ ci->cammode = -1;
init(ci);
dev_info(&i2c->dev, "Attached CXD2099AR at %02x\n", ci->cfg.adr);
return &ci->en;
--
2.1.0

2015-04-08 11:09:13

by Mauro Carvalho Chehab

Subject: Re: [PATCH] media: cxd2099: move pre-init values out of init()

Em Sun, 8 Feb 2015 20:55:36 +0000
luisbg <[email protected]> escreveu:

> Improve code readability by moving out all pre-init values from the init
> function.
>
> Signed-off-by: Luis de Bethencourt <[email protected]>
> ---
> drivers/staging/media/cxd2099/cxd2099.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/staging/media/cxd2099/cxd2099.c b/drivers/staging/media/cxd2099/cxd2099.c
> index 657ea48..bafe36f 100644
> --- a/drivers/staging/media/cxd2099/cxd2099.c
> +++ b/drivers/staging/media/cxd2099/cxd2099.c
> @@ -300,7 +300,6 @@ static int init(struct cxd *ci)
> int status;
>
> mutex_lock(&ci->lock);
> - ci->mode = -1;
> do {
> status = write_reg(ci, 0x00, 0x00);
> if (status < 0)
> @@ -420,7 +419,6 @@ static int init(struct cxd *ci)
> status = write_regm(ci, 0x09, 0x08, 0x08);
> if (status < 0)
> break;
> - ci->cammode = -1;
> cam_mode(ci, 0);
> } while (0);
> mutex_unlock(&ci->lock);
> @@ -711,6 +709,8 @@ struct dvb_ca_en50221 *cxd2099_attach(struct cxd2099_cfg *cfg,
>
> ci->en = en_templ;
> ci->en.data = ci;
> + ci->mode = -1;
> + ci->cammode = -1;

This actually changes the logic, as, cammode is == -1 only if the
do {} while loop succeeds.

Also, calling cam_mode(ci, 0) will change cammode to 0. Btw, for
it to work, ci->mode should be initialized earlier.

So, this patch looks very wrong on my eyes, except if you found
a real bug on it.

Have you tested it on a real device? What bug does it fix?

Regards,
Mauro

> init(ci);
> dev_info(&i2c->dev, "Attached CXD2099AR at %02x\n", ci->cfg.adr);
> return &ci->en;

2015-04-08 12:39:16

by Luis de Bethencourt

Subject: Re: [PATCH] media: cxd2099: move pre-init values out of init()

On Wed, Apr 08, 2015 at 08:09:03AM -0300, Mauro Carvalho Chehab wrote:
> Em Sun, 8 Feb 2015 20:55:36 +0000
> luisbg <[email protected]> escreveu:
>
> > Improve code readability by moving out all pre-init values from the init
> > function.
> >
> > Signed-off-by: Luis de Bethencourt <[email protected]>
> > ---
> > drivers/staging/media/cxd2099/cxd2099.c | 4 ++--
> > 1 file changed, 2 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/staging/media/cxd2099/cxd2099.c b/drivers/staging/media/cxd2099/cxd2099.c
> > index 657ea48..bafe36f 100644
> > --- a/drivers/staging/media/cxd2099/cxd2099.c
> > +++ b/drivers/staging/media/cxd2099/cxd2099.c
> > @@ -300,7 +300,6 @@ static int init(struct cxd *ci)
> > int status;
> >
> > mutex_lock(&ci->lock);
> > - ci->mode = -1;
> > do {
> > status = write_reg(ci, 0x00, 0x00);
> > if (status < 0)
> > @@ -420,7 +419,6 @@ static int init(struct cxd *ci)
> > status = write_regm(ci, 0x09, 0x08, 0x08);
> > if (status < 0)
> > break;
> > - ci->cammode = -1;
> > cam_mode(ci, 0);
> > } while (0);
> > mutex_unlock(&ci->lock);
> > @@ -711,6 +709,8 @@ struct dvb_ca_en50221 *cxd2099_attach(struct cxd2099_cfg *cfg,
> >
> > ci->en = en_templ;
> > ci->en.data = ci;
> > + ci->mode = -1;
> > + ci->cammode = -1;
>
> This actually changes the logic, as, cammode is == -1 only if the
> do {} while loop succeeds.
>
> Also, calling cam_mode(ci, 0) will change cammode to 0. Btw, for
> it to work, ci->mode should be initialized earlier.
>
> So, this patch looks very wrong on my eyes, except if you found
> a real bug on it.
>
> Have you tested it on a real device? What bug does it fix?
>
> Regards,
> Mauro
>

Apologies. You are right and this patch is completely wrong.

I submitted this while reading the code of a few drivers to learn from them.
I should've retracted it before you spent time reviewing it. Sorry for that.

Thanks,
Luis

> > init(ci);
> > dev_info(&i2c->dev, "Attached CXD2099AR at %02x\n", ci->cfg.adr);
> > return &ci->en;