[Intel-wired-lan] [PATCH] ixgbe: fix read-modify-write in x550 phy setup

[Intel-wired-lan] [PATCH] ixgbe: fix read-modify-write in x550 phy setup

[Paul Greenwalt]

Replaced an assignment operation with an OR operation.

The variable assignment was overwriting the value read from the PHY
register. The OR operation sets only the intended register bits.

The bits that were being overwritten are reserved, so the assignment had no
functional impact.

Reported by: Shannon Nelson <shannon.nelson@oracle.com>
Signed-off-by: Paul Greenwalt <paul.greenwalt@intel.com>
---
 drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
index f470d02..3123267 100644
--- a/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
+++ b/drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c
@@ -1847,9 +1847,9 @@ ixgbe_setup_mac_link_sfp_x550a(struct ixgbe_hw *hw, ixgbe_link_speed speed,
 			 (IXGBE_CS4227_EDC_MODE_SR << 1));
 
 	if (setup_linear)
-		reg_phy_ext = (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 1;
+		reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_CX1 << 1) | 1;
 	else
-		reg_phy_ext = (IXGBE_CS4227_EDC_MODE_SR << 1) | 1;
+		reg_phy_ext |= (IXGBE_CS4227_EDC_MODE_SR << 1) | 1;
 
 	ret_val = hw->phy.ops.write_reg(hw, reg_slice,
 					IXGBE_MDIO_ZERO_DEV_TYPE, reg_phy_ext);
-- 
2.7.5

[Intel-wired-lan] [PATCH] ixgbe: fix read-modify-write in x550 phy setup

[Bowers, AndrewX]

> -----Original Message-----
> From: Intel-wired-lan [mailto:intel-wired-lan-bounces at osuosl.org] On
> Behalf Of Paul Greenwalt
> Sent: Thursday, March 15, 2018 5:22 AM
> To: intel-wired-lan at lists.osuosl.org
> Subject: [Intel-wired-lan] [PATCH] ixgbe: fix read-modify-write in x550 phy
> setup
> 
> Replaced an assignment operation with an OR operation.
> 
> The variable assignment was overwriting the value read from the PHY
> register. The OR operation sets only the intended register bits.
> 
> The bits that were being overwritten are reserved, so the assignment had no
> functional impact.
> 
> Reported by: Shannon Nelson <shannon.nelson@oracle.com>
> Signed-off-by: Paul Greenwalt <paul.greenwalt@intel.com>
> ---
>  drivers/net/ethernet/intel/ixgbe/ixgbe_x550.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)

Tested-by: Andrew Bowers <andrewx.bowers@intel.com>