[PATCH] tg3: Fix rx hang on MTU change with 5717/5719

[PATCH] tg3: Fix rx hang on MTU change with 5717/5719

[Brian King]

This fixes a hang issue seen when changing the MTU size from 1500 MTU
to 9000 MTU on both 5717 and 5719 chips. In discussion with Broadcom,
they've indicated that these chipsets have the same phy as the 57766
chipset, so the same workarounds apply. This has been tested by IBM
on both Power 8 and Power 9 systems as well as by Broadcom on x86
hardware and has been confirmed to resolve the hang issue.

Cc: stable <stable@vger.kernel.org>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
---
 drivers/net/ethernet/broadcom/tg3.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
index de51c21..d09c5a9 100644
--- a/drivers/net/ethernet/broadcom/tg3.c
+++ b/drivers/net/ethernet/broadcom/tg3.c
@@ -14225,7 +14225,9 @@ static int tg3_change_mtu(struct net_device *dev, int new_mtu)
 	/* Reset PHY, otherwise the read DMA engine will be in a mode that
 	 * breaks all requests to 256 bytes.
 	 */
-	if (tg3_asic_rev(tp) == ASIC_REV_57766)
+	if (tg3_asic_rev(tp) == ASIC_REV_57766 ||
+	    tg3_asic_rev(tp) == ASIC_REV_5717 ||
+	    tg3_asic_rev(tp) == ASIC_REV_5719)
 		reset_phy = true;
 
 	err = tg3_restart_hw(tp, reset_phy);
-- 
1.8.3.1

Re: [PATCH] tg3: Fix rx hang on MTU change with 5717/5719

[David Miller]

From: Brian King <brking@linux.vnet.ibm.com>
Date: Fri, 15 Dec 2017 15:21:50 -0600

> This fixes a hang issue seen when changing the MTU size from 1500 MTU
> to 9000 MTU on both 5717 and 5719 chips. In discussion with Broadcom,
> they've indicated that these chipsets have the same phy as the 57766
> chipset, so the same workarounds apply. This has been tested by IBM
> on both Power 8 and Power 9 systems as well as by Broadcom on x86
> hardware and has been confirmed to resolve the hang issue.
> 
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Brian King <brking@linux.vnet.ibm.com>

Applied and queued up for -stable.

Please do not add explicit CC: stable tags for networking patches, as
documented in Documentation/networking/netdev-FAQ.txt

Thank you.

Re: [PATCH] tg3: Fix rx hang on MTU change with 5717/5719

[Siva Reddy Kallam]

On Sat, Dec 16, 2017 at 2:51 AM, Brian King <brking@linux.vnet.ibm.com> wrote:
> This fixes a hang issue seen when changing the MTU size from 1500 MTU
> to 9000 MTU on both 5717 and 5719 chips. In discussion with Broadcom,
> they've indicated that these chipsets have the same phy as the 57766
> chipset, so the same workarounds apply. This has been tested by IBM
> on both Power 8 and Power 9 systems as well as by Broadcom on x86
> hardware and has been confirmed to resolve the hang issue.
Thanks for the patch. We need more time to review.
>
> Cc: stable <stable@vger.kernel.org>
> Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
> ---
>  drivers/net/ethernet/broadcom/tg3.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c
> index de51c21..d09c5a9 100644
> --- a/drivers/net/ethernet/broadcom/tg3.c
> +++ b/drivers/net/ethernet/broadcom/tg3.c
> @@ -14225,7 +14225,9 @@ static int tg3_change_mtu(struct net_device *dev, int new_mtu)
>         /* Reset PHY, otherwise the read DMA engine will be in a mode that
>          * breaks all requests to 256 bytes.
>          */
> -       if (tg3_asic_rev(tp) == ASIC_REV_57766)
> +       if (tg3_asic_rev(tp) == ASIC_REV_57766 ||
> +           tg3_asic_rev(tp) == ASIC_REV_5717 ||
> +           tg3_asic_rev(tp) == ASIC_REV_5719)
>                 reset_phy = true;
>
>         err = tg3_restart_hw(tp, reset_phy);
> --
> 1.8.3.1
>