Re: [PATCH] media: dvb: Add error checking for bcm3510_writeB()

[Mauro Carvalho Chehab]

Em Tue,  1 Apr 2025 12:11:41 +0800
Wentao Liang <vulab@xxxxxxxxxxx> escreveu:

> In  bcm3510_bert_reset(), the function performed multiple writes
> without checking the return value of bcm3510_writeB(). This could
> result in silent failures if the writes failed, leaving the BER
> counter in an undefined state.

Did you actually had an issue here with a real hardware? If do, please
describe what happened.

> 
> Add error checking for each bcm3510_writeB call and propagate any
> errors immediately. This ensures proper error handling and prevents
> silent failures during BER counter initialization.
> 
> Fixes: 55f51efdb696 ("[PATCH] dvb: flexcop: add BCM3510 ATSC frontend support for Air2PC card")
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Wentao Liang <vulab@xxxxxxxxxxx>
> ---
>  drivers/media/dvb-frontends/bcm3510.c | 16 ++++++++++++----
>  1 file changed, 12 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/media/dvb-frontends/bcm3510.c b/drivers/media/dvb-frontends/bcm3510.c
> index d935fb10e620..fc5853fc9595 100644
> --- a/drivers/media/dvb-frontends/bcm3510.c
> +++ b/drivers/media/dvb-frontends/bcm3510.c
> @@ -270,10 +270,18 @@ static int bcm3510_bert_reset(struct bcm3510_state *st)
>  	if ((ret = bcm3510_readB(st,0xfa,&b)) < 0)
>  		return ret;
>  
> -	b.BERCTL_fa.RESYNC = 0; bcm3510_writeB(st,0xfa,b);
> -	b.BERCTL_fa.RESYNC = 1; bcm3510_writeB(st,0xfa,b);
> -	b.BERCTL_fa.RESYNC = 0; bcm3510_writeB(st,0xfa,b);
> -	b.BERCTL_fa.CNTCTL = 1; b.BERCTL_fa.BITCNT = 1; bcm3510_writeB(st,0xfa,b);
> +	b.BERCTL_fa.RESYNC = 0;
> +	if ((ret = bcm3510_writeB(st,0xfa,b)) < 0)
> +		return ret;
> +	b.BERCTL_fa.RESYNC = 1;
> +	if ((ret = bcm3510_writeB(st,0xfa,b)) < 0)
> +		return ret;
> +	b.BERCTL_fa.RESYNC = 0;
> +	if ((ret = bcm3510_writeB(st,0xfa,b)) < 0)
> +		return ret;
> +	b.BERCTL_fa.CNTCTL = 1; b.BERCTL_fa.BITCNT = 1;
> +	if ((ret = bcm3510_writeB(st,0xfa,b)) < 0)
> +		return ret;
>  
>  	/* clear residual bit counter TODO  */
>  	return 0;