From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Ananyev, Konstantin" Subject: Re: [PATCH v2] ixgbe: Fix disable interrupt twice Date: Fri, 19 Feb 2016 15:14:06 +0000 Message-ID: <2601191342CEEE43887BDE71AB97725836B0863A@irsmsx105.ger.corp.intel.com> References: <1454046700-20843-1-git-send-email-michael.qiu@intel.com> <1454047090-21274-1-git-send-email-michael.qiu@intel.com> <6A0DE07E22DDAD4C9103DF62FEBC0909034256DA@shsmsx102.ccr.corp.intel.com> <533710CFB86FA344BFBF2D6802E6028622F28091@SHSMSX101.ccr.corp.intel.com> <6A0DE07E22DDAD4C9103DF62FEBC0909034266D1@shsmsx102.ccr.corp.intel.com> <533710CFB86FA344BFBF2D6802E6028622F28A4D@SHSMSX101.ccr.corp.intel.com> <533710CFB86FA344BFBF2D6802E6028622F28B7B@SHSMSX101.ccr.corp.intel.com> <2601191342CEEE43887BDE71AB97725836B02321@irsmsx105.ger.corp.intel.com> <533710CFB86FA344BFBF2D6802E6028622F44907@SHSMSX101.ccr.corp.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable To: "Qiu, Michael" , "Zhang, Helin" , "Lu, Wenzhuo" , "dev@dpdk.org" Return-path: Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by dpdk.org (Postfix) with ESMTP id 9BCB2C44C for ; Fri, 19 Feb 2016 16:14:09 +0100 (CET) In-Reply-To: <533710CFB86FA344BFBF2D6802E6028622F44907@SHSMSX101.ccr.corp.intel.com> Content-Language: en-US List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Hi Michael >=20 > On 2016/2/2 19:03, Ananyev, Konstantin wrote: > > >=20 > [...] >=20 > >>>> I don't think i40e miss it, because it not the right please to disab= le interrupt. > >>>> because all interrupts are enabled in init stage. > >>>> > >>>> Actually, ixgbe enable the interrupt in init stage, but in dev_start= , it disable it > >>>> first and re-enable, so it just the same with doing nothing about in= terrupt. > >>>> > >>>> Just think below: > >>>> > >>>> 1. start the port.(interrupt already enabled in init stage, disable = --> > >>>> re-enable) > >>>> 2. stop the port.(disable interrupt) > >>>> 3. start port again(Try to disable, but failed, already disabled) > >>>> > >>>> Would you think the code has issue? > >>> [Zhang, Helin] in ixgbe PMD, it can be seen that uninit() calls dev_c= lose(), > >>> which calls dev_stop(). So I think the disabling can be done only in = dev_stop(). > >>> All others can make use of dev_stop to disable the interrupt. > >> As I said, if it is in dev_stop, it will has issue when dev_start --> > >> dev_stop --> dev_start, this also could applied in i40e and fm10k. If > >> you want to put it in dev_stop, better to remove enable interrupts in > >> init stage, and only put it in dev_start. > > We can't remove enabling interrupt at init stage and put it only in dev= _start(). > > That means PF couldn't handle interrupts from VF till dev_start() will = be executed on PF > > - which could never happen. > > For same reason we can't disable all interrupts in dev_stop(). > > See: http://dpdk.org/ml/archives/dev/2015-November/027238.html >=20 > Hi, Konstantin >=20 > Yes, you are right. >=20 > So the only way to fix this issue should remove it in dev_stop(), and > left it in uinit() stage, which my patch does. >=20 > Am I right? Yes, I think so. PF should be able to receive MBOX interrupts after dev_stop(). Konstantin >=20 > Thanks, > Michael > > Konstantin > > > >> Thanks, > >> Michael > >>> Regards, > >>> Helin > >>> > >>>> Thanks, > >>>> Michael > >>>> > >>>>> Maybe we can follow fm10k's style. > >>>>> > >>>>>> On other hand, if we remove it in dev_stop, any side effect? In ix= gbe > >>>>>> start, it will always disable it first and then re-enable it, so i= t's safe. > >>>>> I think you mean we can disable intr anyway even if it has been dis= abled. > >>>> Actually, we couldn't, DPDK call VFIO ioctl to kernel to disable int= errupts, and > >>>> if we try disable twice, it will return and error. > >>>> That's why I mean we need a flag to show the interrupts stats. If it= already > >>>> disabled, we do not need call in to kernel. just return and give a w= arning > >>>> message. > >>>> > >>>> Thanks, > >>>> Michael > >>>> > >>>>> Sounds more like why we don't > >>>>> need this patch :) > >>>>> > >>>>>> Thanks, > >>>>>> Michael > >