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=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 B50C7C7618F for ; Mon, 15 Jul 2019 09:03:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 872C120C01 for ; Mon, 15 Jul 2019 09:03:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729495AbfGOJDr (ORCPT ); Mon, 15 Jul 2019 05:03:47 -0400 Received: from gate.crashing.org ([63.228.1.57]:44347 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729394AbfGOJDr (ORCPT ); Mon, 15 Jul 2019 05:03:47 -0400 Received: from localhost (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id x6F93WuZ025986; Mon, 15 Jul 2019 04:03:33 -0500 Message-ID: <25c3813ab1c2943658d7e79756803801b14a34db.camel@kernel.crashing.org> Subject: Re: [PATCH] nvme: Add support for Apple 2018+ models From: Benjamin Herrenschmidt To: Christoph Hellwig Cc: linux-nvme@lists.infradead.org, "linux-kernel@vger.kernel.org" , Keith Busch , Jens Axboe , Paul Pawlowski Date: Mon, 15 Jul 2019 19:03:31 +1000 In-Reply-To: References: <71b009057582cd9c82cff2b45bc1af846408bcf7.camel@kernel.crashing.org> <20190715081041.GB31791@lst.de> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2019-07-15 at 18:43 +1000, Benjamin Herrenschmidt wrote: > On Mon, 2019-07-15 at 10:10 +0200, Christoph Hellwig wrote: > > > + /* > > > + * Apple 2018 and latter variant has a few issues > > > + */ > > > + NVME_QUIRK_APPLE_2018 = (1 << 10), > > > > We try to have quirks for the actual issue, so this should be one quirk > > for the irq vectors issues, and another for the sq entry size. Note that > > NVMe actually has the concept of an I/O queue entry size (IOSQES in the > > Cc register based on values reported in the SQES field in Identify > > Controller. Do these controllers report anything interesting there? > > Ah good to know, I'll dig. Interesting... so SQES is 0x76, indicating that it supports the larger entry size but not that it mandates it. However, we configure CC:IOSQES with 6 and the HW fails unless we have the 128 bytes entry size. So the HW is bogus, but we can probably sort that by doing a better job at fixing up SQES in the identify on the Apple HW, and then actually using it for the SQ. I checked and CC is 0x00460001 so it takes our write of "6" fine. I think they just ignore the value. How do you want to proceed here ? Should I go all the way at attempting to honor sqes "mandatory" size field (and quirk *that*) or just I go the simpler way and stick to shift 6 unless Apple ? If I go the complicated path, should I do the same with cq size (knowing that no known HW has a non-4 mandatory size there and we don't know of a HW bug... yet). Cheers, Ben.