Jeff, Here is a brief description:
The VF driver (ixgbevf) sometimes erroneously concludes that the PF driver has NACK'ed a request. The window where the problem occurs is that the VF driver sends a message to the PF driver, and the PF driver reads the message and sets the IXGBE_PFMAILBOX_ACK. This causes an interrupt on the VF, and in the ixgbevf_msix_mbx() function, we first read the ACK, and then proceed to read the mailbox for a message. Just prior to that, the PF driver acquires the lock on the mailbox to return the response message. The read operation in the VF driver fails because it cannot acquire the lock. An error is logged in the kernel logs. Hope that suffices... Since I am newbie, I have not created signed-off by. Please do me that favor. Thanks, Venu -----Original Message----- From: Jeff Kirsher [mailto:jeffrey.t.kirs...@intel.com] Sent: Wednesday, September 21, 2011 04:18 AM To: Venugopal Busireddy Cc: e1000-devel@lists.sourceforge.net Subject: Re: [E1000-devel] [ixgbevf]: patch to fix incorrect PF NACK assertion... On Tue, 2011-09-20 at 09:36 -0700, Venugopal Busireddy wrote: > diff -r 194e296c8d2e ixgbevf_main.c > --- a/ixgbevf_main.c Thu Sep 15 10:46:23 2011 -0500 > +++ b/ixgbevf_main.c Thu Sep 15 10:47:08 2011 -0500 > @@ -997,15 +997,18 @@ > if (!hw->mbx.ops.check_for_ack(hw, 0)) > got_ack = true; > > - hw->mbx.ops.read(hw, &msg, 1, 0); > - > - if ((msg & IXGBE_MBVFICR_VFREQ_MASK) == IXGBE_PF_CONTROL_MSG) > - mod_timer(&adapter->watchdog_timer, > - round_jiffies(jiffies + 1)); > - > - if (msg & IXGBE_VT_MSGTYPE_NACK) > - DPRINTK(DRV, ERR, "Last Request of type %2.2x to PF Nacked\n", > - msg & 0xFF); > + if (!hw->mbx.ops.check_for_msg(hw, 0)) { > + hw->mbx.ops.read(hw, &msg, 1, 0); > + > + if ((msg & IXGBE_MBVFICR_VFREQ_MASK) == IXGBE_PF_CONTROL_MSG) > + mod_timer(&adapter->watchdog_timer, > + round_jiffies(jiffies + 1)); > + > + if (msg & IXGBE_VT_MSGTYPE_NACK) > + DPRINTK(DRV, ERR, > + "Last Request of type %2.2x to PF Nacked\n", > + msg & 0xFF); > + } > > /* > * checking for the ack clears the PFACK bit. Place Thanks! I have added the patch to my queue for ixgbevf. Since there is no patch description & signed-off-by, do you mind if I create one? Since you are the author of this patch, I will set you as the author and add you signed-off-by. ------------------------------------------------------------------------------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 _______________________________________________ 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
