From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Vick, Matthew" Subject: Re: [PATCH] igb: fix PHC stopping on max freq Date: Tue, 19 Mar 2013 21:17:25 +0000 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: "e1000-devel@lists.sourceforge.net" , Miroslav Lichvar , Stefan Assmann To: Jiri Benc , "netdev@vger.kernel.org" Return-path: In-Reply-To: Content-Language: en-US Content-ID: <1FB41EFDCD2D7643BD2E822460EF9C9D@intel.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: e1000-devel-bounces@lists.sourceforge.net List-Id: netdev.vger.kernel.org On 3/19/13 7:42 AM, "Jiri Benc" wrote: >For 82576 MAC type, max_adj is reported as 1000000000 ppb. However, if >this value is passed to igb_ptp_adjfreq_82576, incvalue overflows out of >INCVALUE_82576_MASK, resulting in setting of zero TIMINCA.incvalue, >stopping >the PHC (instead of going at twice the nominal speed). > >Fix the advertised max_adj value to the largest value hardware can handle. >As there is no min_adj value available (-max_adj is used instead), this >will >also prevent stopping the clock intentionally. It's probably not a big >deal, >other igb MAC types don't support stopping the clock, either. > >Signed-off-by: Jiri Benc >--- > drivers/net/ethernet/intel/igb/igb_ptp.c | 2 +- > 1 files changed, 1 insertions(+), 1 deletions(-) > >diff --git a/drivers/net/ethernet/intel/igb/igb_ptp.c >b/drivers/net/ethernet/intel/igb/igb_ptp.c >index 0987822..0a23750 100644 >--- a/drivers/net/ethernet/intel/igb/igb_ptp.c >+++ b/drivers/net/ethernet/intel/igb/igb_ptp.c >@@ -740,7 +740,7 @@ void igb_ptp_init(struct igb_adapter *adapter) > case e1000_82576: > snprintf(adapter->ptp_caps.name, 16, "%pm", netdev->dev_addr); > adapter->ptp_caps.owner = THIS_MODULE; >- adapter->ptp_caps.max_adj = 1000000000; >+ adapter->ptp_caps.max_adj = 999999881; > adapter->ptp_caps.n_ext_ts = 0; > adapter->ptp_caps.pps = 0; > adapter->ptp_caps.adjfreq = igb_ptp_adjfreq_82576; >-- >1.7.6.5 Good catch on this, Jiri! I know the math works out the same, but I'd prefer it if you changed the max_adj value to 999999999, since that is technically what we can accept before we have any issues. If you re-submit with this change, I'll add my ACK and we can run it through our internal testing. Thanks! Matthew Matthew Vick Linux Development Networking Division Intel Corporation ------------------------------------------------------------------------------ Everyone hates slow websites. So do we. Make your web apps faster with AppDynamics Download AppDynamics Lite for free today: http://p.sf.net/sfu/appdyn_d2d_mar _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired