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From: Greg KH <gregkh@linuxfoundation.org>
To: Punnay Sharma <punnaysharma805@gmail.com>
Cc: mchehab@kernel.org, error27@gmail.com,
	linux-media@vger.kernel.org, linux-staging@lists.linux.dev,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v2 1/2] staging: media: av7110: fix corrupted BER reporting in sp8870
Date: Sat, 8 Aug 2026 07:45:23 +0200	[thread overview]
Message-ID: <2026080813-dimness-mammal-e7e9@gregkh> (raw)
In-Reply-To: <20260807183443.13912-1-punnaysharma805@gmail.com>

On Sat, Aug 08, 2026 at 12:04:42AM +0530, Punnay Sharma wrote:
> In sp8870_read_ber(), the 14-bit Bit Error Rate (BER) is assembled by
> reading two I2C registers: 0xC08 (lower 6 bits) and 0xC07 (upper 8 bits).
> 
> The current implementation masks the lower bits via `tmp = ret & 0x3F;`
> but subsequently overwrites `tmp` entirely when processing the upper
> bits using a direct assignment (`tmp = ret << 6;`). This logical error
> causes the lower 6 bits of the BER hardware metric to be silently
> discarded.
> 
> Fix this by using a bitwise OR (`tmp |= ret << 6;`) to correctly merge
> the MSB and LSB payloads before returning the metric to the DVB core.
> 
> Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
> Signed-off-by: Punnay Sharma <punnaysharma805@gmail.com>
> ---
>  drivers/staging/media/av7110/sp8870.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/staging/media/av7110/sp8870.c b/drivers/staging/media/av7110/sp8870.c
> index 29fb4934c..77bebf2c7 100644
> --- a/drivers/staging/media/av7110/sp8870.c
> +++ b/drivers/staging/media/av7110/sp8870.c
> @@ -401,7 +401,7 @@ static int sp8870_read_ber(struct dvb_frontend *fe, u32 *ber)
>  	if (ret < 0)
>  		return -EIO;
>  
> -	tmp = ret << 6;
> +	tmp |= ret << 6;
>  	if (tmp >= 0x3FFF0)
>  		tmp = ~0;
>  
> -- 
> 2.55.0
> 
> 

Did you forget the Assisted-by: tag?

      parent reply	other threads:[~2026-08-08  5:45 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-07 18:34 [PATCH v2 1/2] staging: media: av7110: fix corrupted BER reporting in sp8870 Punnay Sharma
2026-08-07 18:34 ` [PATCH v2 2/2] staging: media: av7110: fix sp8870 initialization failure state Punnay Sharma
2026-08-07 18:46 ` [PATCH v2 1/2] staging: media: av7110: fix corrupted BER reporting in sp8870 Dan Carpenter
2026-08-08  5:45 ` Greg KH [this message]

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