2017-09-05 16:32:53

by Colin King

Subject: [PATCH] staging: rtl8192u: fix incorrect mask when calculating TxPowerLevelCCK

From: Colin Ian King <[email protected]>

The mask of 0xff and right shift of 8 bits on ret always results in
a value of 0 for TxPowerLevelCCK. I believe this should be a mask of
0xff00, however I do not have the hardware at hand to test this out,
so there is a distinct possibility I may be wrong on this.

Detected by CoverityScan CID#1357110 ("Operands don't affect result")

Signed-off-by: Colin Ian King <[email protected]>
---
drivers/staging/rtl8192u/r8192U_core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
index 46b3f19e0878..ecc887636173 100644
--- a/drivers/staging/rtl8192u/r8192U_core.c
+++ b/drivers/staging/rtl8192u/r8192U_core.c
@@ -2510,7 +2510,7 @@ static int rtl8192_read_eeprom_info(struct net_device *dev)
ret = eprom_read(dev, (EEPROM_TxPwIndex_CCK >> 1));
if (ret < 0)
return ret;
- priv->EEPROMTxPowerLevelCCK = ((u16)ret & 0xff) >> 8;
+ priv->EEPROMTxPowerLevelCCK = ((u16)ret & 0xff00) >> 8;
} else
priv->EEPROMTxPowerLevelCCK = 0x10;
RT_TRACE(COMP_EPROM, "CCK Tx Power Levl: 0x%02x\n", priv->EEPROMTxPowerLevelCCK);
--
2.14.1

2017-09-05 17:00:58

by walter harms

Subject: Re: [PATCH] staging: rtl8192u: fix incorrect mask when calculating TxPowerLevelCCK

Am 05.09.2017 18:32, schrieb Colin King:
> From: Colin Ian King <[email protected]>
>
> The mask of 0xff and right shift of 8 bits on ret always results in
> a value of 0 for TxPowerLevelCCK. I believe this should be a mask of
> 0xff00, however I do not have the hardware at hand to test this out,
> so there is a distinct possibility I may be wrong on this.
>
> Detected by CoverityScan CID#1357110 ("Operands don't affect result")
>
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/staging/rtl8192u/r8192U_core.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/staging/rtl8192u/r8192U_core.c b/drivers/staging/rtl8192u/r8192U_core.c
> index 46b3f19e0878..ecc887636173 100644
> --- a/drivers/staging/rtl8192u/r8192U_core.c
> +++ b/drivers/staging/rtl8192u/r8192U_core.c
> @@ -2510,7 +2510,7 @@ static int rtl8192_read_eeprom_info(struct net_device *dev)
> ret = eprom_read(dev, (EEPROM_TxPwIndex_CCK >> 1));
> if (ret < 0)
> return ret;
> - priv->EEPROMTxPowerLevelCCK = ((u16)ret & 0xff) >> 8;
> + priv->EEPROMTxPowerLevelCCK = ((u16)ret & 0xff00) >> 8;

Is there any need for the mask ?
(u16) will already reduce ret to 16 bit, the >>8 will shift the lower bits into nirwana

re,
wh

> } else
> priv->EEPROMTxPowerLevelCCK = 0x10;
> RT_TRACE(COMP_EPROM, "CCK Tx Power Levl: 0x%02x\n", priv->EEPROMTxPowerLevelCCK);