[PATCH v2 1/2] staging: media: av7110: fix corrupted BER reporting in sp8870

From: Punnay Sharma

Date: Fri Aug 07 2026 - 14:35:59 EST


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@xxxxxxxxx>
---
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