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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9F116C433F5 for ; Fri, 10 Dec 2021 19:05:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232410AbhLJTJP (ORCPT ); Fri, 10 Dec 2021 14:09:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235649AbhLJTJN (ORCPT ); Fri, 10 Dec 2021 14:09:13 -0500 Received: from mail-oi1-x235.google.com (mail-oi1-x235.google.com [IPv6:2607:f8b0:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EEE14C0617A1 for ; Fri, 10 Dec 2021 11:05:37 -0800 (PST) Received: by mail-oi1-x235.google.com with SMTP id bf8so14502755oib.6 for ; Fri, 10 Dec 2021 11:05:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=eE7LEXLBndGG1htPQ+DXNYXDObvNjAlKpnwTZx768wc=; b=eOJZva4Fq1luajmeTCOHeGthRyrZdIKhZ514Ze8syFWhn42iAWp7fHREQ1llf+rnDP ZoGAUfQfUQypcyflo52/gGgBIDeJZOKno5WHENWSjVzvVt0KVkBlO8u2JdtlUvojfjKq DIuCjPkbyA4Xw/5bIkLz/mYo5me9MEVPZcquO57vWajLufnnl5JnDfqxeqopN/lS5KJY z2u9qNDMw7d0dhFLu62zkU89T2qZrO/ie5Ui3gifR6q0YwnuTzPdJsqat0eRbrqQRfbg x7pjc6o2jFtWU5qATsl3I/6HW/J3YnO/WKzqe4jr3LVPBk1zBUdlMhIlYkhCv/KhKENu 4o3g== 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=eE7LEXLBndGG1htPQ+DXNYXDObvNjAlKpnwTZx768wc=; b=dsJqgAzGma6K87I+lbAQ0OeZ+O+Kj0NQvUw0wO1+xZY66z2liLuqMCttxehNj6ln6y cjl/eFlcoiA5LE4q8fS2IVjV60iB97F2Ze4rc4W+P+SJ6okvWqigF4HDLja4xB/XYOuf sd0JbUOMMz7K7t7gnoIolPUgtDeaSQf7Wz5aukrMTWlXin+0vir6GsBiQuiZniYYcS1y yfci0E615vwsylmHX0CkDb3ngsMqs09GYesjUGRerkiD8K6fCY2Vv0dxZTVF4zUkmEE3 kghwfd6QEo4aef6kn5eakPj7e5HMNrLprkD6EGhGDgxWHCN5zrRraeXRWzEdt6i508Vw EWrg== X-Gm-Message-State: AOAM531S1ZO9Cy7cW97Bnb4WOAQyXIHBz2zem7fNbkHZeGlOSRdR3rtg F8zKtQF6/+mZb2InitNq3bO/7GyU/pY1zU3qIcQ= X-Google-Smtp-Source: ABdhPJwY+3OIlLMQRK831jBALf9pBKI0vv9FSDO/7G8EZuTphIx/zK41Uwd0OUE7wTRPguj3+nvRSAdElVT9nmALC7Y= X-Received: by 2002:a05:6808:68f:: with SMTP id k15mr13685527oig.5.1639163136150; Fri, 10 Dec 2021 11:05:36 -0800 (PST) MIME-Version: 1.0 References: <62aab616-53cb-ff9f-c5f3-169c547bd1ee@igalia.com> <6d3c7acf-a23f-3073-56ed-375ccb8cc815@suse.de> <99b38881-8c63-de04-50f8-aa4119b52b25@igalia.com> <56dfb915-036b-0584-f0ef-83c786970d6e@igalia.com> In-Reply-To: <56dfb915-036b-0584-f0ef-83c786970d6e@igalia.com> From: Alex Deucher Date: Fri, 10 Dec 2021 14:05:25 -0500 Message-ID: Subject: Re: Reuse framebuffer after a kexec (amdgpu / efifb) To: "Guilherme G. Piccoli" Cc: Thomas Zimmermann , Gerd Hoffmann , "open list:EFIFB FRAMEBUFFER DRIVER" , kexec@lists.infradead.org, amd-gfx list , kernel@gpiccoli.net, Baoquan He , =?UTF-8?Q?Samuel_Iglesias_Gons=C3=A1lvez?= , xinhui pan , Maling list - DRI developers , pjones@redhat.com, "Deucher, Alexander" , Dave Young , Christian Koenig , Vivek Goyal Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org On Fri, Dec 10, 2021 at 9:25 AM Guilherme G. Piccoli wrote: > > On 10/12/2021 11:16, Alex Deucher wrote:> [...] > > Why not just reload the driver after kexec? > > > > Alex > > Because the original issue is the kdump case, and we want a very very > tiny kernel - also, the crash originally could have been caused by > amdgpu itself, so if it's a GPU issue, we don't want to mess with that > in kdump. And I confess I tried modprobe amdgpu after a kdump, no > success - kdump won't call shutdown handlers, so GPU will be in a > "rogue" state... > > My question was about regular kexec because it's much simpler usually, > we can do whatever we want there. My line of thought was: if I make it > work in regular kexec with a simple framebuffer, I might be able to get > it working on kdump heheh > Well if the GPU is hung, I'm not sure if you'll be able to get back the display environment without a GPU reset and once you do that, you've lost any state you might have been trying to preserve. Alex