diff mbox series

[v2,net] smsc95xx: Ignore -ENODEV errors when device is unplugged

Message ID 20220305204720.2978554-1-festevam@gmail.com (mailing list archive)
State Accepted
Commit c70c453abcbf3ecbaadd4c3236a5119b8da365cf
Delegated to: Netdev Maintainers
Headers show
Series [v2,net] smsc95xx: Ignore -ENODEV errors when device is unplugged | expand

Checks

Context Check Description
netdev/tree_selection success Clearly marked for net
netdev/fixes_present success Fixes tag present in non-next series
netdev/subject_prefix success Link
netdev/cover_letter success Single patches do not need cover letters
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 1 this patch: 1
netdev/cc_maintainers fail 1 blamed authors not CCed: davem@davemloft.net; 1 maintainers not CCed: davem@davemloft.net
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/verify_fixes success Fixes tag looks correct
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 76 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Fabio Estevam March 5, 2022, 8:47 p.m. UTC 
From: Fabio Estevam <festevam@denx.de>

According to Documentation/driver-api/usb/URB.rst when a device
is unplugged usb_submit_urb() returns -ENODEV.

This error code propagates all the way up to usbnet_read_cmd() and
usbnet_write_cmd() calls inside the smsc95xx.c driver during
Ethernet cable unplug, unbind or reboot.

This causes the following errors to be shown on reboot, for example:

ci_hdrc ci_hdrc.1: remove, state 1
usb usb2: USB disconnect, device number 1
usb 2-1: USB disconnect, device number 2
usb 2-1.1: USB disconnect, device number 3
smsc95xx 2-1.1:1.0 eth1: unregister 'smsc95xx' usb-ci_hdrc.1-1.1, smsc95xx USB 2.0 Ethernet
smsc95xx 2-1.1:1.0 eth1: Failed to read reg index 0x00000114: -19
smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
smsc95xx 2-1.1:1.0 eth1: Failed to read reg index 0x00000114: -19
smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
smsc95xx 2-1.1:1.0 eth1: hardware isn't capable of remote wakeup
usb 2-1.4: USB disconnect, device number 4
ci_hdrc ci_hdrc.1: USB bus 2 deregistered
ci_hdrc ci_hdrc.0: remove, state 4
usb usb1: USB disconnect, device number 1
ci_hdrc ci_hdrc.0: USB bus 1 deregistered
imx2-wdt 30280000.watchdog: Device shutdown: Expect reboot!
reboot: Restarting system

Ignore the -ENODEV errors inside __smsc95xx_mdio_read() and
__smsc95xx_phy_wait_not_busy() and do not print error messages
when -ENODEV is returned.

Fixes: a049a30fc27c ("net: usb: Correct PHY handling of smsc95xx")
Signed-off-by: Fabio Estevam <festevam@denx.de>
---
Changes since v1:
- Added 'net' annotation - Andrew
- Added Fixes tag - Andrew
- Avoided undefined 'buf' behaviour in __smsc95xx_read_reg() - Andrew

 drivers/net/usb/smsc95xx.c | 28 ++++++++++++++++++++--------
 1 file changed, 20 insertions(+), 8 deletions(-)

Comments

patchwork-bot+netdevbpf@kernel.org March 7, 2022, 12:40 p.m. UTC | #1 
Hello:

This patch was applied to netdev/net.git (master)
by David S. Miller <davem@davemloft.net>:

On Sat,  5 Mar 2022 17:47:20 -0300 you wrote:
> From: Fabio Estevam <festevam@denx.de>
> 
> According to Documentation/driver-api/usb/URB.rst when a device
> is unplugged usb_submit_urb() returns -ENODEV.
> 
> This error code propagates all the way up to usbnet_read_cmd() and
> usbnet_write_cmd() calls inside the smsc95xx.c driver during
> Ethernet cable unplug, unbind or reboot.
> 
> [...]

Here is the summary with links:
  - [v2,net] smsc95xx: Ignore -ENODEV errors when device is unplugged
    https://git.kernel.org/netdev/net/c/c70c453abcbf

You are awesome, thank you!
Alexander Stein March 9, 2022, 1:32 p.m. UTC | #2 
Hello Fabio,

Am Samstag, 5. März 2022, 21:47:20 CET schrieb Fabio Estevam:
> From: Fabio Estevam <festevam@denx.de>
> 
> According to Documentation/driver-api/usb/URB.rst when a device
> is unplugged usb_submit_urb() returns -ENODEV.
> 
> This error code propagates all the way up to usbnet_read_cmd() and
> usbnet_write_cmd() calls inside the smsc95xx.c driver during
> Ethernet cable unplug, unbind or reboot.
> 
> This causes the following errors to be shown on reboot, for example:
> 
> ci_hdrc ci_hdrc.1: remove, state 1
> usb usb2: USB disconnect, device number 1
> usb 2-1: USB disconnect, device number 2
> usb 2-1.1: USB disconnect, device number 3
> smsc95xx 2-1.1:1.0 eth1: unregister 'smsc95xx' usb-ci_hdrc.1-1.1, smsc95xx
> USB 2.0 Ethernet smsc95xx 2-1.1:1.0 eth1: Failed to read reg index
> 0x00000114: -19
> smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
> smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
> smsc95xx 2-1.1:1.0 eth1: Failed to read reg index 0x00000114: -19
> smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
> smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
> smsc95xx 2-1.1:1.0 eth1: hardware isn't capable of remote wakeup
> usb 2-1.4: USB disconnect, device number 4
> ci_hdrc ci_hdrc.1: USB bus 2 deregistered
> ci_hdrc ci_hdrc.0: remove, state 4
> usb usb1: USB disconnect, device number 1
> ci_hdrc ci_hdrc.0: USB bus 1 deregistered
> imx2-wdt 30280000.watchdog: Device shutdown: Expect reboot!
> reboot: Restarting system
> 
> Ignore the -ENODEV errors inside __smsc95xx_mdio_read() and
> __smsc95xx_phy_wait_not_busy() and do not print error messages
> when -ENODEV is returned.

Just FYI, this even fixed a suspend problem on a 5.10 imx downstream kernel 
which had similar symptoms. Thanks a lot.

Regards
Alexander

> Fixes: a049a30fc27c ("net: usb: Correct PHY handling of smsc95xx")
> Signed-off-by: Fabio Estevam <festevam@denx.de>
> ---
> Changes since v1:
> - Added 'net' annotation - Andrew
> - Added Fixes tag - Andrew
> - Avoided undefined 'buf' behaviour in __smsc95xx_read_reg() - Andrew
> 
>  drivers/net/usb/smsc95xx.c | 28 ++++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
> index b17bff6a1015..e5b744851146 100644
> --- a/drivers/net/usb/smsc95xx.c
> +++ b/drivers/net/usb/smsc95xx.c
> @@ -84,9 +84,10 @@ static int __must_check __smsc95xx_read_reg(struct usbnet
> *dev, u32 index, ret = fn(dev, USB_VENDOR_REQUEST_READ_REGISTER, USB_DIR_IN
> 
>  		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> 
>  		 0, index, &buf, 4);
> -	if (unlikely(ret < 0)) {
> -		netdev_warn(dev->net, "Failed to read reg index 0x%08x: 
%d\n",
> -			    index, ret);
> +	if (ret < 0) {
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Failed to read reg 
index 0x%08x: %d\n",
> +				    index, ret);
>  		return ret;
>  	}
> 
> @@ -116,7 +117,7 @@ static int __must_check __smsc95xx_write_reg(struct
> usbnet *dev, u32 index, ret = fn(dev, USB_VENDOR_REQUEST_WRITE_REGISTER,
> USB_DIR_OUT
> 
>  		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> 
>  		 0, index, &buf, 4);
> -	if (unlikely(ret < 0))
> +	if (ret < 0 && ret != -ENODEV)
>  		netdev_warn(dev->net, "Failed to write reg index 0x%08x: 
%d\n",
>  			    index, ret);
> 
> @@ -159,6 +160,9 @@ static int __must_check
> __smsc95xx_phy_wait_not_busy(struct usbnet *dev, do {
>  		ret = __smsc95xx_read_reg(dev, MII_ADDR, &val, in_pm);
>  		if (ret < 0) {
> +			/* Ignore -ENODEV error during disconnect() 
*/
> +			if (ret == -ENODEV)
> +				return 0;
>  			netdev_warn(dev->net, "Error reading 
MII_ACCESS\n");
>  			return ret;
>  		}
> @@ -194,7 +198,8 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx, addr = mii_address_cmd(phy_id, idx, MII_READ_ |
> MII_BUSY_);
>  	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_ADDR\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_ADDR\n");
>  		goto done;
>  	}
> 
> @@ -206,7 +211,8 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx,
> 
>  	ret = __smsc95xx_read_reg(dev, MII_DATA, &val, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error reading MII_DATA\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error reading 
MII_DATA\n");
>  		goto done;
>  	}
> 
> @@ -214,6 +220,10 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx,
> 
>  done:
>  	mutex_unlock(&dev->phy_mutex);
> +
> +	/* Ignore -ENODEV error during disconnect() */
> +	if (ret == -ENODEV)
> +		return 0;
>  	return ret;
>  }
> 
> @@ -235,7 +245,8 @@ static void __smsc95xx_mdio_write(struct usbnet *dev,
> int phy_id, val = regval;
>  	ret = __smsc95xx_write_reg(dev, MII_DATA, val, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_DATA\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_DATA\n");
>  		goto done;
>  	}
> 
> @@ -243,7 +254,8 @@ static void __smsc95xx_mdio_write(struct usbnet *dev,
> int phy_id, addr = mii_address_cmd(phy_id, idx, MII_WRITE_ | MII_BUSY_);
>  	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_ADDR\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_ADDR\n");
>  		goto done;
>  	}
Alexander Stein March 9, 2022, 2:02 p.m. UTC | #3 
Am Samstag, 5. März 2022, 21:47:20 CET schrieb Fabio Estevam:
> From: Fabio Estevam <festevam@denx.de>
> 
> According to Documentation/driver-api/usb/URB.rst when a device
> is unplugged usb_submit_urb() returns -ENODEV.
> 
> This error code propagates all the way up to usbnet_read_cmd() and
> usbnet_write_cmd() calls inside the smsc95xx.c driver during
> Ethernet cable unplug, unbind or reboot.
> 
> This causes the following errors to be shown on reboot, for example:
> 
> ci_hdrc ci_hdrc.1: remove, state 1
> usb usb2: USB disconnect, device number 1
> usb 2-1: USB disconnect, device number 2
> usb 2-1.1: USB disconnect, device number 3
> smsc95xx 2-1.1:1.0 eth1: unregister 'smsc95xx' usb-ci_hdrc.1-1.1, smsc95xx
> USB 2.0 Ethernet smsc95xx 2-1.1:1.0 eth1: Failed to read reg index
> 0x00000114: -19
> smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
> smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
> smsc95xx 2-1.1:1.0 eth1: Failed to read reg index 0x00000114: -19
> smsc95xx 2-1.1:1.0 eth1: Error reading MII_ACCESS
> smsc95xx 2-1.1:1.0 eth1: __smsc95xx_mdio_read: MII is busy
> smsc95xx 2-1.1:1.0 eth1: hardware isn't capable of remote wakeup
> usb 2-1.4: USB disconnect, device number 4
> ci_hdrc ci_hdrc.1: USB bus 2 deregistered
> ci_hdrc ci_hdrc.0: remove, state 4
> usb usb1: USB disconnect, device number 1
> ci_hdrc ci_hdrc.0: USB bus 1 deregistered
> imx2-wdt 30280000.watchdog: Device shutdown: Expect reboot!
> reboot: Restarting system
> 
> Ignore the -ENODEV errors inside __smsc95xx_mdio_read() and
> __smsc95xx_phy_wait_not_busy() and do not print error messages
> when -ENODEV is returned.
> 
> Fixes: a049a30fc27c ("net: usb: Correct PHY handling of smsc95xx")
> Signed-off-by: Fabio Estevam <festevam@denx.de>

Oh BTW, is this queued for stable? Which versions? If 'Fixes: a049a30fc27c 
("net: usb: Correct PHY handling of smsc95xx")' is the indicator, it's not 
enough. This errors also shows up on v5.15.27 and is fixed with this patch.

Regards,
Alexander

> ---
> Changes since v1:
> - Added 'net' annotation - Andrew
> - Added Fixes tag - Andrew
> - Avoided undefined 'buf' behaviour in __smsc95xx_read_reg() - Andrew
> 
>  drivers/net/usb/smsc95xx.c | 28 ++++++++++++++++++++--------
>  1 file changed, 20 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
> index b17bff6a1015..e5b744851146 100644
> --- a/drivers/net/usb/smsc95xx.c
> +++ b/drivers/net/usb/smsc95xx.c
> @@ -84,9 +84,10 @@ static int __must_check __smsc95xx_read_reg(struct usbnet
> *dev, u32 index, ret = fn(dev, USB_VENDOR_REQUEST_READ_REGISTER, USB_DIR_IN
> 
>  		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> 
>  		 0, index, &buf, 4);
> -	if (unlikely(ret < 0)) {
> -		netdev_warn(dev->net, "Failed to read reg index 0x%08x: 
%d\n",
> -			    index, ret);
> +	if (ret < 0) {
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Failed to read reg 
index 0x%08x: %d\n",
> +				    index, ret);
>  		return ret;
>  	}
> 
> @@ -116,7 +117,7 @@ static int __must_check __smsc95xx_write_reg(struct
> usbnet *dev, u32 index, ret = fn(dev, USB_VENDOR_REQUEST_WRITE_REGISTER,
> USB_DIR_OUT
> 
>  		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
> 
>  		 0, index, &buf, 4);
> -	if (unlikely(ret < 0))
> +	if (ret < 0 && ret != -ENODEV)
>  		netdev_warn(dev->net, "Failed to write reg index 0x%08x: 
%d\n",
>  			    index, ret);
> 
> @@ -159,6 +160,9 @@ static int __must_check
> __smsc95xx_phy_wait_not_busy(struct usbnet *dev, do {
>  		ret = __smsc95xx_read_reg(dev, MII_ADDR, &val, in_pm);
>  		if (ret < 0) {
> +			/* Ignore -ENODEV error during disconnect() 
*/
> +			if (ret == -ENODEV)
> +				return 0;
>  			netdev_warn(dev->net, "Error reading 
MII_ACCESS\n");
>  			return ret;
>  		}
> @@ -194,7 +198,8 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx, addr = mii_address_cmd(phy_id, idx, MII_READ_ |
> MII_BUSY_);
>  	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_ADDR\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_ADDR\n");
>  		goto done;
>  	}
> 
> @@ -206,7 +211,8 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx,
> 
>  	ret = __smsc95xx_read_reg(dev, MII_DATA, &val, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error reading MII_DATA\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error reading 
MII_DATA\n");
>  		goto done;
>  	}
> 
> @@ -214,6 +220,10 @@ static int __smsc95xx_mdio_read(struct usbnet *dev, int
> phy_id, int idx,
> 
>  done:
>  	mutex_unlock(&dev->phy_mutex);
> +
> +	/* Ignore -ENODEV error during disconnect() */
> +	if (ret == -ENODEV)
> +		return 0;
>  	return ret;
>  }
> 
> @@ -235,7 +245,8 @@ static void __smsc95xx_mdio_write(struct usbnet *dev,
> int phy_id, val = regval;
>  	ret = __smsc95xx_write_reg(dev, MII_DATA, val, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_DATA\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_DATA\n");
>  		goto done;
>  	}
> 
> @@ -243,7 +254,8 @@ static void __smsc95xx_mdio_write(struct usbnet *dev,
> int phy_id, addr = mii_address_cmd(phy_id, idx, MII_WRITE_ | MII_BUSY_);
>  	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
>  	if (ret < 0) {
> -		netdev_warn(dev->net, "Error writing MII_ADDR\n");
> +		if (ret != -ENODEV)
> +			netdev_warn(dev->net, "Error writing 
MII_ADDR\n");
>  		goto done;
>  	}
Jakub Kicinski March 9, 2022, 4:41 p.m. UTC | #4 
On Wed, 09 Mar 2022 15:02:21 +0100 Alexander Stein wrote:
> > Fixes: a049a30fc27c ("net: usb: Correct PHY handling of smsc95xx")
> > Signed-off-by: Fabio Estevam <festevam@denx.de>  
> 
> Oh BTW, is this queued for stable? Which versions? If 'Fixes: a049a30fc27c 
> ("net: usb: Correct PHY handling of smsc95xx")' is the indicator, it's not 
> enough. This errors also shows up on v5.15.27 and is fixed with this patch.

The stable machinery will most likely suck it in automatically.
The patch should reach Linus tomorrow evening if you want to ping 
Greg and make sure.
Fabio Estevam March 9, 2022, 4:50 p.m. UTC | #5 
Hi Alexander,

On Wed, Mar 9, 2022 at 11:02 AM Alexander Stein
<alexander.stein@ew.tq-group.com> wrote:

> Oh BTW, is this queued for stable? Which versions? If 'Fixes: a049a30fc27c
> ("net: usb: Correct PHY handling of smsc95xx")' is the indicator, it's not
> enough. This errors also shows up on v5.15.27 and is fixed with this patch.

("net: usb: Correct PHY handling of smsc95xx")' is also present in 5.15:
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/log/drivers/net/usb/smsc95xx.c?h=v5.15.27

so the fix should land in 5.15 too.

For 5.10, when the fix reaches Linus' tree, then I will ping
Dave/Jakub/Greg to apply the 3 latest smsc95xx commits
to 5.10 stable tree:
https://git.kernel.org/pub/scm/linux/kernel/git/netdev/net.git/log/drivers/net/usb/smsc95xx.c?id=c70c453abcbf

I have been running 5.10 + the 3 commits above and no more smsc95xx
errors are seen.
diff mbox series

Patch

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index b17bff6a1015..e5b744851146 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c
@@ -84,9 +84,10 @@  static int __must_check __smsc95xx_read_reg(struct usbnet *dev, u32 index,
 	ret = fn(dev, USB_VENDOR_REQUEST_READ_REGISTER, USB_DIR_IN
 		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 		 0, index, &buf, 4);
-	if (unlikely(ret < 0)) {
-		netdev_warn(dev->net, "Failed to read reg index 0x%08x: %d\n",
-			    index, ret);
+	if (ret < 0) {
+		if (ret != -ENODEV)
+			netdev_warn(dev->net, "Failed to read reg index 0x%08x: %d\n",
+				    index, ret);
 		return ret;
 	}
 
@@ -116,7 +117,7 @@  static int __must_check __smsc95xx_write_reg(struct usbnet *dev, u32 index,
 	ret = fn(dev, USB_VENDOR_REQUEST_WRITE_REGISTER, USB_DIR_OUT
 		 | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
 		 0, index, &buf, 4);
-	if (unlikely(ret < 0))
+	if (ret < 0 && ret != -ENODEV)
 		netdev_warn(dev->net, "Failed to write reg index 0x%08x: %d\n",
 			    index, ret);
 
@@ -159,6 +160,9 @@  static int __must_check __smsc95xx_phy_wait_not_busy(struct usbnet *dev,
 	do {
 		ret = __smsc95xx_read_reg(dev, MII_ADDR, &val, in_pm);
 		if (ret < 0) {
+			/* Ignore -ENODEV error during disconnect() */
+			if (ret == -ENODEV)
+				return 0;
 			netdev_warn(dev->net, "Error reading MII_ACCESS\n");
 			return ret;
 		}
@@ -194,7 +198,8 @@  static int __smsc95xx_mdio_read(struct usbnet *dev, int phy_id, int idx,
 	addr = mii_address_cmd(phy_id, idx, MII_READ_ | MII_BUSY_);
 	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
 	if (ret < 0) {
-		netdev_warn(dev->net, "Error writing MII_ADDR\n");
+		if (ret != -ENODEV)
+			netdev_warn(dev->net, "Error writing MII_ADDR\n");
 		goto done;
 	}
 
@@ -206,7 +211,8 @@  static int __smsc95xx_mdio_read(struct usbnet *dev, int phy_id, int idx,
 
 	ret = __smsc95xx_read_reg(dev, MII_DATA, &val, in_pm);
 	if (ret < 0) {
-		netdev_warn(dev->net, "Error reading MII_DATA\n");
+		if (ret != -ENODEV)
+			netdev_warn(dev->net, "Error reading MII_DATA\n");
 		goto done;
 	}
 
@@ -214,6 +220,10 @@  static int __smsc95xx_mdio_read(struct usbnet *dev, int phy_id, int idx,
 
 done:
 	mutex_unlock(&dev->phy_mutex);
+
+	/* Ignore -ENODEV error during disconnect() */
+	if (ret == -ENODEV)
+		return 0;
 	return ret;
 }
 
@@ -235,7 +245,8 @@  static void __smsc95xx_mdio_write(struct usbnet *dev, int phy_id,
 	val = regval;
 	ret = __smsc95xx_write_reg(dev, MII_DATA, val, in_pm);
 	if (ret < 0) {
-		netdev_warn(dev->net, "Error writing MII_DATA\n");
+		if (ret != -ENODEV)
+			netdev_warn(dev->net, "Error writing MII_DATA\n");
 		goto done;
 	}
 
@@ -243,7 +254,8 @@  static void __smsc95xx_mdio_write(struct usbnet *dev, int phy_id,
 	addr = mii_address_cmd(phy_id, idx, MII_WRITE_ | MII_BUSY_);
 	ret = __smsc95xx_write_reg(dev, MII_ADDR, addr, in_pm);
 	if (ret < 0) {
-		netdev_warn(dev->net, "Error writing MII_ADDR\n");
+		if (ret != -ENODEV)
+			netdev_warn(dev->net, "Error writing MII_ADDR\n");
 		goto done;
 	}