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 X-Spam-Level: X-Spam-Status: No, score=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EC2ABCA9EB7 for ; Tue, 22 Oct 2019 18:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id CEEDF21906 for ; Tue, 22 Oct 2019 18:24:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732446AbfJVSYu (ORCPT ); Tue, 22 Oct 2019 14:24:50 -0400 Received: from mail-qk1-f193.google.com ([209.85.222.193]:43353 "EHLO mail-qk1-f193.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727226AbfJVSYt (ORCPT ); Tue, 22 Oct 2019 14:24:49 -0400 Received: by mail-qk1-f193.google.com with SMTP id a194so13114985qkg.10 for ; Tue, 22 Oct 2019 11:24:48 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=6a2nV0MVVlfJzNZnPnOTDLrt++nGC/Q++LUC46+Srfs=; b=B7m7JsBJsWKVw3wfzfsT/zcjS8PLZ5UgZiG0O24kuzjlryiQbYwwQXFIZ1SpwMZKvf emTWQOrp5Unu0z6DLbDlDEZ/csmuv+n3F1FX4hLkYUK8MM7uZp1n6FD1BvyoP/llsqAY cG9NdURv9NpIM7Zu0lgEkbzlIf2kv85J7bD21HXRU0R/Azi1Mmi3UIsPlxoB1rm59FAO VGkH47FOd6V/iD2ETTmesPMlbLgN0eR2zcE5WjeyL7Wt/FUg1Lusg5auIR/Eky3k8F2V mMb3meXPZ8jv/QSh/aw4EK53AK0uJMb6L39bAfsMI7Af5EGmf/JDZrushF/sUENMUKkb DDBQ== X-Gm-Message-State: APjAAAXUzfxTHzmflxwwU5/PIoq4o9CIxM7IA0rMH3O6V3Tta6dDSvdt ZXH5jzEqCg3OkfmOWtkIeTJ+h3XkUvgDBu+R9Quv8Q== X-Google-Smtp-Source: APXvYqx9mOfVbCYC9GsKFZa4fGYTxPWRK90Y0l+O0nTsCrcQwbRGfHV+Trm4l5Z1EWT36RNpBdbMKGjLmtkMaFyycY8= X-Received: by 2002:a37:67d6:: with SMTP id b205mr4512027qkc.183.1571768688431; Tue, 22 Oct 2019 11:24:48 -0700 (PDT) MIME-Version: 1.0 References: <1571734629-18028-1-git-send-email-zhichen@codeaurora.org> In-Reply-To: From: Adrian Chadd Date: Tue, 22 Oct 2019 11:24:36 -0700 Message-ID: Subject: Re: [PATCH RFC] Revert "ath10k: fix DMA related firmware crashes on multiple devices" To: Peter Oh Cc: Zhi Chen , ath10k , linux-wireless@vger.kernel.org Content-Type: text/plain; charset="UTF-8" Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Tue, 22 Oct 2019 at 10:17, Peter Oh wrote: > > > On 10/22/19 1:57 AM, Zhi Chen wrote: > > This reverts commit 76d164f582150fd0259ec0fcbc485470bcd8033e. > > PCIe hung issue was observed on multiple platforms. The issue was reproduced > > when DUT was configured as AP and associated with 50+ STAs. > > > > With PCIe protocol analyzer, we can see DMA Read crossing 4KB boundary when > > issue happened. It broke PCIe spec and caused PCIe stuck. > > How can you say value 0 (I believe it's 64 bytes) DMA burst size causes > the symptom and 1 fixes it? +1 to this question. Also, shouldn't the DMA engine be doing what the firmware says? Is the firmware/copy engine actually somehow bursting / prefetching across a 4K page boundary? Surely this is something that can be fixed in software/firmware by correctly configuring up buffer size/offsets? -adrian