ACK: [SRU][Trusty][PATCH 1/1] e1000e: Fix no connectivity when driver loaded with cable out

[Luis Henriques]

On Wed, Dec 17, 2014 at 12:00:51PM -0500, Joseph Salisbury wrote:
> From: David Ertman <davidx.m.ertman at intel.com>
> 
> BugLink: http://bugs.launchpad.net/bugs/1400365
> 
> In commit da1e2046e5, the flow for enabling/disabling an Si errata
> workaround (e1000_lv_jumbo_workaround_ich8lan) was changed to fix a problem
> with iAMT connections dropping on interface down with jumbo frames set.
> Part of this change was to move the function call disabling the workaround
> to e1000e_down() from the e1000_setup_rctl() function.  The mechanic for
> disabling of this workaround involves writing several MAC and PHY registers
> back to hardware defaults.
> 
> After this commit, when the driver is loaded with the cable out, the PHY
> registers are not programmed with the correct default values.  This causes
> the device to be capable of transmitting packets, but is unable to recieve
> them until this workaround is called.
> 
> The flow of e1000e's open code relies upon calling the above workaround to
> expicitly program these registers either with jumbo frame appropriate settings
> or h/w defaults on 82579 and newer hardware.
> 
> Fix this issue by adding logic to e1000_setup_rctl() that not only calls
> e1000_lv_jumbo_workaround_ich8lan() when jumbo frames are set, to enable the
> workaround, but also calls this function to explicitly disable the workaround
> in the case that jumbo frames are not set.
> 
> Signed-off-by: Dave Ertman <davidx.m.ertman at intel.com>
> Tested-by: Jeff Pieper <jeffrey.e.pieper at intel.com>
> Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher at intel.com>
> (cherry picked from commit b20a774495671f037e7160ea2ce8789af6b61533)
> 
> Signed-off-by: Joseph Salisbury <joseph.salisbury at canonical.com>
> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c |   20 +++++++++++++++-----
>  1 file changed, 15 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index 6d14eea..a205f8d 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -2976,11 +2976,21 @@ static void e1000_setup_rctl(struct e1000_adapter *adapter)
>  	u32 rctl, rfctl;
>  	u32 pages = 0;
>  
> -	/* Workaround Si errata on PCHx - configure jumbo frame flow */
> -	if ((hw->mac.type >= e1000_pch2lan) &&
> -	    (adapter->netdev->mtu > ETH_DATA_LEN) &&
> -	    e1000_lv_jumbo_workaround_ich8lan(hw, true))
> -		e_dbg("failed to enable jumbo frame workaround mode\n");
> +	/* Workaround Si errata on PCHx - configure jumbo frame flow.
> +	 * If jumbo frames not set, program related MAC/PHY registers
> +	 * to h/w defaults
> +	 */
> +	if (hw->mac.type >= e1000_pch2lan) {
> +		s32 ret_val;
> +
> +		if (adapter->netdev->mtu > ETH_DATA_LEN)
> +			ret_val = e1000_lv_jumbo_workaround_ich8lan(hw, true);
> +		else
> +			ret_val = e1000_lv_jumbo_workaround_ich8lan(hw, false);
> +
> +		if (ret_val)
> +			e_dbg("failed to enable|disable jumbo frame workaround mode\n");
> +	}
>  
>  	/* Program MC offset vector base */
>  	rctl = er32(RCTL);
> -- 
> 1.7.9.5
> 
> 
> -- 
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Seems OK to me, and it includes positive testing feedback.

Cheers,
--
Luís