[PATCH] igb: skip phy status check where unavailable

[PATCH] igb: skip phy status check where unavailable

[Kevin Mitchell]

igb_read_phy_reg() will silently return, leaving phy_data untouched, if
hw->ops.read_reg isn't set. Depending on the uninitialized value of
phy_data, this led to the phy status check either succeeding immediately
or looping continuously for 2 seconds before emitting a noisy err-level
timeout. This message went out to the console even though there was no
actual problem.

Instead, first check if there is read_reg function pointer. If not,
proceed without trying to check the phy status register.

Fixes: b72f3f72005d ("igb: When GbE link up, wait for Remote receiver status condition")
Signed-off-by: Kevin Mitchell <kevmitch@arista.com>
---
 drivers/net/ethernet/intel/igb/igb_main.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 34b33b21e0dc..68be2976f539 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -5505,7 +5505,8 @@ static void igb_watchdog_task(struct work_struct *work)
 				break;
 			}
 
-			if (adapter->link_speed != SPEED_1000)
+			if (adapter->link_speed != SPEED_1000 ||
+			    !hw->phy.ops.read_reg)
 				goto no_wait;
 
 			/* wait for Remote receiver status OK */
-- 
2.35.1

RE: [Intel-wired-lan] [PATCH] igb: skip phy status check where unavailable

[G, GurucharanX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Kevin Mitchell
> Sent: Saturday, April 30, 2022 5:26 AM
> Cc: kevmitch@arista.com; intel-wired-lan@lists.osuosl.org; linux-
> kernel@vger.kernel.org; Takuma Ueba <t.ueba11@gmail.com>; Jeff Kirsher
> <jeffrey.t.kirsher@intel.com>; netdev@vger.kernel.org; Jakub Kicinski
> <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; David S. Miller
> <davem@davemloft.net>
> Subject: [Intel-wired-lan] [PATCH] igb: skip phy status check where
> unavailable
> 
> igb_read_phy_reg() will silently return, leaving phy_data untouched, if
> hw->ops.read_reg isn't set. Depending on the uninitialized value of
> phy_data, this led to the phy status check either succeeding immediately or
> looping continuously for 2 seconds before emitting a noisy err-level timeout.
> This message went out to the console even though there was no actual
> problem.
> 
> Instead, first check if there is read_reg function pointer. If not, proceed
> without trying to check the phy status register.
> 
> Fixes: b72f3f72005d ("igb: When GbE link up, wait for Remote receiver status
> condition")
> Signed-off-by: Kevin Mitchell <kevmitch@arista.com>
> ---
>  drivers/net/ethernet/intel/igb/igb_main.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 

Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)

RE: [Intel-wired-lan] [PATCH] igb: skip phy status check where unavailable

[G, GurucharanX]

> -----Original Message-----
> From: Intel-wired-lan <intel-wired-lan-bounces@osuosl.org> On Behalf Of
> Kevin Mitchell
> Sent: Saturday, April 30, 2022 5:26 AM
> Cc: kevmitch@arista.com; intel-wired-lan@lists.osuosl.org; linux-
> kernel@vger.kernel.org; Takuma Ueba <t.ueba11@gmail.com>; Jeff Kirsher
> <jeffrey.t.kirsher@intel.com>; netdev@vger.kernel.org; Jakub Kicinski
> <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; David S. Miller
> <davem@davemloft.net>
> Subject: [Intel-wired-lan] [PATCH] igb: skip phy status check where
> unavailable
> 
> igb_read_phy_reg() will silently return, leaving phy_data untouched, if
> hw->ops.read_reg isn't set. Depending on the uninitialized value of
> phy_data, this led to the phy status check either succeeding immediately or
> looping continuously for 2 seconds before emitting a noisy err-level timeout.
> This message went out to the console even though there was no actual
> problem.
> 
> Instead, first check if there is read_reg function pointer. If not, proceed
> without trying to check the phy status register.
> 
> Fixes: b72f3f72005d ("igb: When GbE link up, wait for Remote receiver status
> condition")
> Signed-off-by: Kevin Mitchell <kevmitch@arista.com>
> ---
>  drivers/net/ethernet/intel/igb/igb_main.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 

Tested-by: Gurucharan <gurucharanx.g@intel.com> (A Contingent worker at Intel)