From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5F4D7C433F5 for ; Mon, 18 Oct 2021 12:00:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4589661260 for ; Mon, 18 Oct 2021 12:00:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231408AbhJRMDH (ORCPT ); Mon, 18 Oct 2021 08:03:07 -0400 Received: from mail-ua1-f48.google.com ([209.85.222.48]:38667 "EHLO mail-ua1-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229781AbhJRMDG (ORCPT ); Mon, 18 Oct 2021 08:03:06 -0400 Received: by mail-ua1-f48.google.com with SMTP id h19so1338642uax.5; Mon, 18 Oct 2021 05:00:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=ugxvHlyhTx50acGfMe/mBaSIaa61RPwcWtMFE4GIscE=; b=bfRrL+TT5fmZo9pkcjzKK5yBNCMErvsBKVqz0FXGHZ0SOtAmzudb5ULoBYQEw4fooA vlTOAB0N1N+g41t309WUBYirwVwDzj1MRGJqD8MH/HdspmhQ2W2bcGahL7JIfUS9pwk4 pUSDKcUKK5NjZMUKiP2XNYSEodrfFd43IS+ARlYahXgrkV9RUVwOsI8QrKZHS2HB9ybc GIY4Ck429aB28LQ+NvtDKignebNT4+lUharV60OdgdF5CMRVE6xObJ6zyFRB8JNDr/x4 YUTApWrvBxZuPaAdNV6QQ341AYIWMRxeJw1uVwPThoaUMEpOS6BRqXTju9fmXjmq06ZR WJ6Q== X-Gm-Message-State: AOAM533j6U0KCLuDUndoLfnyagUB2ZDVeFRZd/utnRJ89S6b7Uu65KHv HJDJCXVB9kYeYLdeKvreWL4gcgM1c9JHzA== X-Google-Smtp-Source: ABdhPJxZj6oTviogUpxy2XG9HDxo278AeoyYwykpTNMh31ZNZHC3751eCp97gONrTSh8lMpEy/BRVA== X-Received: by 2002:a67:f70a:: with SMTP id m10mr26722758vso.40.1634558454897; Mon, 18 Oct 2021 05:00:54 -0700 (PDT) Received: from mail-ua1-f49.google.com (mail-ua1-f49.google.com. [209.85.222.49]) by smtp.gmail.com with ESMTPSA id o40sm7954384vkf.3.2021.10.18.05.00.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 18 Oct 2021 05:00:54 -0700 (PDT) Received: by mail-ua1-f49.google.com with SMTP id q13so3137848uaq.2; Mon, 18 Oct 2021 05:00:54 -0700 (PDT) X-Received: by 2002:ab0:3d9a:: with SMTP id l26mr893052uac.114.1634558453426; Mon, 18 Oct 2021 05:00:53 -0700 (PDT) MIME-Version: 1.0 References: <2544a93bf8725eecbea510e7ddbff6b5a5593c84.1634306198.git.naveennaidu479@gmail.com> <20211018115148.iwhiknpd6o4okudq@theprophet> In-Reply-To: <20211018115148.iwhiknpd6o4okudq@theprophet> From: Geert Uytterhoeven Date: Mon, 18 Oct 2021 14:00:41 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 14/24] PCI: rcar: Remove redundant error fabrication when device read fails To: Naveen Naidu Cc: Bjorn Helgaas , linux-kernel-mentees@lists.linuxfoundation.org, linux-pci , Linux Kernel Mailing List , Marek Vasut , Yoshihiro Shimoda , Lorenzo Pieralisi , Rob Herring , =?UTF-8?Q?Krzysztof_Wilczy=C5=84ski?= , "open list:PCI DRIVER FOR RENESAS R-CAR" Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hi Naveen, On Mon, Oct 18, 2021 at 1:52 PM Naveen Naidu wrote: > On 18/10, Geert Uytterhoeven wrote: > > On Sat, Oct 16, 2021 at 5:33 PM Naveen Naidu wrote: > > > An MMIO read from a PCI device that doesn't exist or doesn't respond > > > causes a PCI error. There's no real data to return to satisfy the > > > CPU read, so most hardware fabricates ~0 data. > > > > > > The host controller drivers sets the error response values (~0) and > > > returns an error when faulty hardware read occurs. But the error > > > response value (~0) is already being set in PCI_OP_READ and > > > PCI_USER_READ_CONFIG whenever a read by host controller driver fails. > > > > > > Thus, it's no longer necessary for the host controller drivers to > > > fabricate any error response. > > > > > > This helps unify PCI error response checking and make error check > > > consistent and easier to find. > > > > > > Signed-off-by: Naveen Naidu > > > > Thanks for your patch! > > > > > --- a/drivers/pci/controller/pcie-rcar-host.c > > > +++ b/drivers/pci/controller/pcie-rcar-host.c > > > @@ -161,10 +161,8 @@ static int rcar_pcie_read_conf(struct pci_bus *bus, unsigned int devfn, > > > > > > ret = rcar_pcie_config_access(host, RCAR_PCI_ACCESS_READ, > > > bus, devfn, where, val); > > > - if (ret != PCIBIOS_SUCCESSFUL) { > > > - *val = 0xffffffff; > > > > I don't see the behavior you describe in PCI_OP_READ(), so dropping > > this will lead to returning an uninitialized value? > > > > Hello Geert, > > Thank you for looking into the patch. > > The described behaviour for PCI_OP_READ is part of the 01/24 [1] patch of > the series. > > [1]: > https://lore.kernel.org/linux-pci/b913b4966938b7cad8c049dc34093e6c4b2fae68.1634306198.git.naveennaidu479@gmail.com/T/#u OK, in that case: Reviewed-by: Geert Uytterhoeven > It looks like, I did not add proper receipients for that patch and hence > is leading to confusion. I really apologize for that. Indeed. If there are dependencies, all recipients should receive all dependencies. > I do not know what the right approach here should be, should I resend > the entire patch series, adding proper receipients OR should I reply to > each of the patches for the drivers and add the link to the patch. I did > not want to spam people with a lot of mails so I was confused as to what > the right option is. Probably a resend would be best. Thanks! Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds