From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH v2 10/16] Added support for selecting VFIO interrupt type from EAL command-line Date: Tue, 20 May 2014 04:23:23 -0700 Message-ID: <20140520042323.4dbea108@samsung-9> References: <1400514709-24087-11-git-send-email-anatoly.burakov@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: "dev-VfR2kkLFssw@public.gmane.org" To: "Burakov, Anatoly" Return-path: In-Reply-To: List-Id: patches and discussions about DPDK List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces-VfR2kkLFssw@public.gmane.org Sender: "dev" On Tue, 20 May 2014 08:33:43 +0000 "Burakov, Anatoly" wrote: > Hi Stephen, > > > I really wish the code did automatic fall back based on PCI config. It is possible to know the right mode, and do the right thing. > > Rather than punting the problem out to command line which is totally unusable in hot plug and generic application. > > You mean we should use whatever is available rather than default to MSI-X if nothing was explicitly specified? That could be done, I guess. > > Best regards, > Anatoly Burakov > DPDK SW Engineer > > I am not sure that MSI-X has any advantage with only one IRQ, so MSI would do. Then have the code look at the PCI capability of device and fallback to INTX if needed. It should also check if INTX works, see kernel for details, since some PCI emulation like VMware is broken.