From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH 2/2] uio: new driver to support PCI MSI-X Date: Thu, 1 Oct 2015 17:01:45 -0700 Message-ID: <20151001170145.4239de9f@urahara> References: <1443652138-31782-1-git-send-email-stephen@networkplumber.org> <1443652138-31782-3-git-send-email-stephen@networkplumber.org> <560DC45A.3050507@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: dev@dpdk.org, hjk@hansjkoch.de, gregkh@linux-foundation.org, linux-kernel@vger.kernel.org To: Alexander Duyck Return-path: Received: from mail-pa0-f53.google.com (mail-pa0-f53.google.com [209.85.220.53]) by dpdk.org (Postfix) with ESMTP id 9F6A48E61 for ; Fri, 2 Oct 2015 02:01:36 +0200 (CEST) Received: by pacfv12 with SMTP id fv12so90787322pac.2 for ; Thu, 01 Oct 2015 17:01:36 -0700 (PDT) In-Reply-To: <560DC45A.3050507@gmail.com> 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" On Thu, 1 Oct 2015 16:40:10 -0700 Alexander Duyck wrote: > I agree with some other reviewers. Why call pci_enable_msix in open? > It seems like it would make much more sense to do this on probe, and > then disable MSI-X on free. I can only assume you are trying to do it > to save on resources but the fact is this is a driver you have to > explicitly force onto a device so you would probably be safe to assume > that they plan to use it in the near future. Because if interface is not up, the MSI handle doesn't have to be open. This saves resources and avoids some races.