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 93EC6C433EF for ; Wed, 17 Nov 2021 19:01:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6E4F861A58 for ; Wed, 17 Nov 2021 19:01:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231810AbhKQTET convert rfc822-to-8bit (ORCPT ); Wed, 17 Nov 2021 14:04:19 -0500 Received: from coyote.holtmann.net ([212.227.132.17]:40956 "EHLO mail.holtmann.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229580AbhKQTES (ORCPT ); Wed, 17 Nov 2021 14:04:18 -0500 Received: from smtpclient.apple (p4fefc15c.dip0.t-ipconnect.de [79.239.193.92]) by mail.holtmann.org (Postfix) with ESMTPSA id AE6D9CECF6; Wed, 17 Nov 2021 20:01:17 +0100 (CET) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 15.0 \(3693.20.0.1.32\)) Subject: Re: [PATCHv2] Bluetooth: quirk disabling LE Read Transmit Power From: Marcel Holtmann In-Reply-To: <20211117124717.12352-1-redecorating@protonmail.com> Date: Wed, 17 Nov 2021 20:01:17 +0100 Cc: regressions@leemhuis.info, danielwinkler@google.com, gargaditya08@live.com, gregkh@linuxfoundation.org, Johan Hedberg , linux-bluetooth@vger.kernel.org, linux-kernel@vger.kernel.org, Luiz Augusto von Dentz , regressions@lists.linux.dev, sonnysasaka@chromium.org Content-Transfer-Encoding: 8BIT Message-Id: References: <20211001083412.3078-1-redecorating@protonmail.com> <70a875d0-7162-d149-dbc1-c2f5e1a8e701@leemhuis.info> <20211116090128.17546-1-redecorating@protonmail.com> <3B8E16FA-97BF-40E5-9149-BBC3E2A245FE@live.com> <52DEDC31-EEB2-4F39-905F-D5E3F2BBD6C0@live.com> <8919a36b-e485-500a-2722-529ffa0d2598@leemhuis.info> <20211117124717.12352-1-redecorating@protonmail.com> To: Orlando Chamberlain X-Mailer: Apple Mail (2.3693.20.0.1.32) Precedence: bulk List-ID: X-Mailing-List: linux-bluetooth@vger.kernel.org Hi Orlando, >> So if this just affects two macs, why can't the fix be realized as a >> quirk that is only enabled on those two systems? Or are they impossible >> to detect clearly via DMI data or something like that? > > I think we should be able to quirk based off the acpi _CID "apple-uart-blth" > or _HID "BCM2E7C". Marcel suggested quirking based of the acpi table here > https://lore.kernel.org/linux-bluetooth/1D2217A9-EA73-4D93-8D0B-5BC2718D4788@holtmann.org/ > > This would catch some unaffected Macs, but they don't support the LE Read > Transmit Power command anyway (the affected macs were released after it > was added to the Bluetooth spec, while the unaffected Macs were released > before it was added to the spec, and thus don't support it). > > I'm not sure how to go about applying a quirk based off this, there are > quirks in drivers/bluetooth/hci_bcm.c (no_early_set_baudrate and > drive_rts_on_open), but they don't seem to be based off acpi ids. > > It might be simpler to make it ignore the Unknown Command error, like > in this patch https://lore.kernel.org/linux-bluetooth/CABBYNZLjSfcG_KqTEbL6NOSvHhA5-b1t_S=3FQP4=GwW21kuzg@mail.gmail.com/ > however that only applies on bluetooth-next and needed the status it > checks for to be -56, not 0x01. so we abstain from try-and-error sending of commands. The Bluetooth spec has a list of supported commands that a host can query for a reason. This is really broken behavior of the controller and needs to be pointed out as such. The question is just how we quirk it. Regards Marcel