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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 B0756C433B4 for ; Thu, 13 May 2021 08:11:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6F45061422 for ; Thu, 13 May 2021 08:11:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231695AbhEMIMQ convert rfc822-to-8bit (ORCPT ); Thu, 13 May 2021 04:12:16 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([185.58.85.151]:29954 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231521AbhEMIML (ORCPT ); Thu, 13 May 2021 04:12:11 -0400 Received: from AcuMS.aculab.com (156.67.243.121 [156.67.243.121]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-38-wSN3IdVMP8OQ2JQTBB0LqA-1; Thu, 13 May 2021 09:10:56 +0100 X-MC-Unique: wSN3IdVMP8OQ2JQTBB0LqA-1 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) by AcuMS.aculab.com (fd9f:af1c:a25b:0:994c:f5c2:35d6:9b65) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 13 May 2021 09:10:55 +0100 Received: from AcuMS.Aculab.com ([fe80::994c:f5c2:35d6:9b65]) by AcuMS.aculab.com ([fe80::994c:f5c2:35d6:9b65%12]) with mapi id 15.00.1497.015; Thu, 13 May 2021 09:10:55 +0100 From: David Laight To: 'Maximilian Luz' , Thomas Gleixner , Ingo Molnar , Borislav Petkov CC: "H. Peter Anvin" , Sachi King , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "stable@vger.kernel.org" Subject: RE: [PATCH] x86/i8259: Work around buggy legacy PIC Thread-Topic: [PATCH] x86/i8259: Work around buggy legacy PIC Thread-Index: AQHXR3+B5Hf0DG1T80+Lb/Y+9zG7TarhDftg Date: Thu, 13 May 2021 08:10:54 +0000 Message-ID: <9b70d8113c084848b8d9293c4428d71b@AcuMS.aculab.com> References: <20210512210459.1983026-1-luzmaximilian@gmail.com> In-Reply-To: <20210512210459.1983026-1-luzmaximilian@gmail.com> Accept-Language: en-GB, en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=C51A453 smtp.mailfrom=david.laight@aculab.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: aculab.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Maximilian Luz > Sent: 12 May 2021 22:05 > > The legacy PIC on the AMD variant of the Microsoft Surface Laptop 4 has > some problems on boot. For some reason it consistently does not respond > on the first try, requiring a couple more tries before it finally > responds. That seems very strange, something else must be going on that causes the grief. The 8259 will be built into to the one of the cpu support chips. I can't imagine that requires anything special. It's not as though you have a real 8259 - which even a 286 can break the inter-cycle recovery on (with the circuit from the application note). David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)