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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 38C7DD44C7E for ; Thu, 15 Jan 2026 16:40:03 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id 5F7AE10E7A0; Thu, 15 Jan 2026 16:40:03 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="Ajgs/5uV"; dkim-atps=neutral Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 452F210E7A0; Thu, 15 Jan 2026 16:40:02 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 425D460128; Thu, 15 Jan 2026 16:40:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE65FC116D0; Thu, 15 Jan 2026 16:39:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768495201; bh=m/Qx1m1mblaNipkWax3IZgERtuZ8Zkg6ma1HJe/Md/E=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Ajgs/5uVyXu7H8VC4ngrms4uARgCVFYOon/i7wj+tn1w72j7H9T4CM/BxlZwd5lfS ArM+/+rYU3rKnLV6+pVVvz2xEyrpoFlBKWFw0boo3efTETsCmzQu/ZE0OeVtl0dB+f OsIA6BVINFZuD/IWhl5QhJw7xQ/V3+KuhWleDmm2Uu0LE4mBpC5uY2z5TWKQR60521 okmZ3GiKI4O0OQKRcKN8BhBRretfYIV+o+nSHwdJyyofS2pOTXfPpeZVnq7A8/4fqQ 5muGt/pK+Fzt9ilSvbB4X7VBJVKErM24M547oE1T0H0ecZk5Yym+Nzm5jURgtti7jE zgal0OGtjOvSg== Message-ID: Date: Thu, 15 Jan 2026 10:39:56 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/12] Recover sysfb after DRM probe failure To: Gerd Hoffmann , =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= Cc: =?UTF-8?Q?Christian_K=C3=B6nig?= , Thomas Zimmermann , Zack Rusin , dri-devel@lists.freedesktop.org, Alex Deucher , amd-gfx@lists.freedesktop.org, Ard Biesheuvel , Ce Sun , Chia-I Wu , Danilo Krummrich , Dave Airlie , Deepak Rawat , Dmitry Osipenko , Gurchetan Singh , Hans de Goede , Hawking Zhang , Helge Deller , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Jani Nikula , Javier Martinez Canillas , Jocelyn Falempe , Joonas Lahtinen , Lijo Lazar , linux-efi@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, Lucas De Marchi , Lyude Paul , Maarten Lankhorst , Mario Limonciello , Maxime Ripard , nouveau@lists.freedesktop.org, Rodrigo Vivi , Simona Vetter , spice-devel@lists.freedesktop.org, =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= , =?UTF-8?Q?Timur_Krist=C3=B3f?= , Tvrtko Ursulin , virtualization@lists.linux.dev, Vitaly Prosyak References: <20251229215906.3688205-1-zack.rusin@broadcom.com> <97993761-5884-4ada-b345-9fb64819e02a@suse.de> <9058636d-cc18-4c8f-92cf-782fd8f771af@amd.com> Content-Language: en-US From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: amd-gfx@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Discussion list for AMD gfx List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces@lists.freedesktop.org Sender: "amd-gfx" On 1/15/26 10:36 AM, Gerd Hoffmann wrote: > Hi, > >>> At least for AMD GPUs remove_conflicting_devices() really early is >>> necessary because otherwise some operations just result in a >>> spontaneous system reboot. > >> It's similar for Intel. For us VGA emulation won't be used for EFI >> boot, but we still can't have the previous driver poking around in >> memory while the real driver is initializing. The entire memory layout >> may get completely shuffled so there's no telling where such memory >> accesses would land. > > Can you do stuff like checking which firmware is needed and whenever > that can be loaded from the filesystem before calling > remove_conflicting_devices() ? > That's something that I did in amdgpu a few years back. I pushed the identification and ability to load firmware into early init stages. It means that if you have a brand new GPU and run a modern kernel with an older linux-firmware snapshot amdgpu will fail probe and your framebuffer from EFI keeps working. 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 gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 35D9DD44C73 for ; Thu, 15 Jan 2026 16:40:08 +0000 (UTC) Received: from kara.freedesktop.org (unknown [131.252.210.166]) by gabe.freedesktop.org (Postfix) with ESMTPS id 74FBD10E7B2; Thu, 15 Jan 2026 16:40:05 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.b="Ajgs/5uV"; dkim-atps=neutral Received: from kara.freedesktop.org (localhost [127.0.0.1]) by kara.freedesktop.org (Postfix) with ESMTP id D6A6A44CB4; Thu, 15 Jan 2026 16:31:31 +0000 (UTC) ARC-Seal: i=1; cv=none; a=rsa-sha256; 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mail.freedesktop.org; dkim=pass header.d=kernel.org; arc=none (Message is not ARC signed); dmarc=pass (Used From Domain Record) header.from=kernel.org policy.dmarc=quarantine Authentication-Results: mail.freedesktop.org; dkim=pass header.d=kernel.org; arc=none (Message is not ARC signed); dmarc=pass (Used From Domain Record) header.from=kernel.org policy.dmarc=quarantine Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) by kara.freedesktop.org (Postfix) with ESMTPS id 0E4B844C9F for ; Thu, 15 Jan 2026 16:31:29 +0000 (UTC) Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by gabe.freedesktop.org (Postfix) with ESMTPS id 452F210E7A0; Thu, 15 Jan 2026 16:40:02 +0000 (UTC) Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 425D460128; Thu, 15 Jan 2026 16:40:01 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id BE65FC116D0; Thu, 15 Jan 2026 16:39:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1768495201; bh=m/Qx1m1mblaNipkWax3IZgERtuZ8Zkg6ma1HJe/Md/E=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=Ajgs/5uVyXu7H8VC4ngrms4uARgCVFYOon/i7wj+tn1w72j7H9T4CM/BxlZwd5lfS ArM+/+rYU3rKnLV6+pVVvz2xEyrpoFlBKWFw0boo3efTETsCmzQu/ZE0OeVtl0dB+f OsIA6BVINFZuD/IWhl5QhJw7xQ/V3+KuhWleDmm2Uu0LE4mBpC5uY2z5TWKQR60521 okmZ3GiKI4O0OQKRcKN8BhBRretfYIV+o+nSHwdJyyofS2pOTXfPpeZVnq7A8/4fqQ 5muGt/pK+Fzt9ilSvbB4X7VBJVKErM24M547oE1T0H0ecZk5Yym+Nzm5jURgtti7jE zgal0OGtjOvSg== Message-ID: Date: Thu, 15 Jan 2026 10:39:56 -0600 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 00/12] Recover sysfb after DRM probe failure To: Gerd Hoffmann , =?UTF-8?B?VmlsbGUgU3lyasOkbMOk?= References: <20251229215906.3688205-1-zack.rusin@broadcom.com> <97993761-5884-4ada-b345-9fb64819e02a@suse.de> <9058636d-cc18-4c8f-92cf-782fd8f771af@amd.com> Content-Language: en-US From: Mario Limonciello In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Message-ID-Hash: J2GYUBAFS5MSQ3ESOLYBIOAHGHL24A5N X-Message-ID-Hash: J2GYUBAFS5MSQ3ESOLYBIOAHGHL24A5N X-MailFrom: superm1@kernel.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: =?UTF-8?Q?Christian_K=C3=B6nig?= , Zack Rusin , dri-devel@lists.freedesktop.org, Alex Deucher , amd-gfx@lists.freedesktop.org, Ard Biesheuvel , Ce Sun , Chia-I Wu , Danilo Krummrich , Dave Airlie , Deepak Rawat , Dmitry Osipenko , Gurchetan Singh , Hans de Goede , Hawking Zhang , Helge Deller , intel-gfx@lists.freedesktop.org, intel-xe@lists.freedesktop.org, Jani Nikula , Javier Martinez Canillas , Jocelyn Falempe , Joonas Lahtinen , Lijo Lazar , linux-efi@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org, Lucas De Marchi , Maarten Lankhorst , Mario Limonciello , Maxime Ripard , nouveau@lists.freedesktop.org, Rodrigo Vivi , Simona Vetter , spice-devel@lists.freedesktop.org, =?UTF-8?Q?Thomas_Hellstr=C3=B6m?= , =?UTF-8?Q?Timur_Krist=C3=B3f?= , Tvrtko Ursulin , virtualization@lists.linux.dev, Vitaly Prosyak X-Mailman-Version: 3.3.8 Precedence: list List-Id: Nouveau development list Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On 1/15/26 10:36 AM, Gerd Hoffmann wrote: > Hi, > >>> At least for AMD GPUs remove_conflicting_devices() really early is >>> necessary because otherwise some operations just result in a >>> spontaneous system reboot. > >> It's similar for Intel. For us VGA emulation won't be used for EFI >> boot, but we still can't have the previous driver poking around in >> memory while the real driver is initializing. The entire memory layout >> may get completely shuffled so there's no telling where such memory >> accesses would land. > > Can you do stuff like checking which firmware is needed and whenever > that can be loaded from the filesystem before calling > remove_conflicting_devices() ? > That's something that I did in amdgpu a few years back. I pushed the identification and ability to load firmware into early init stages. It means that if you have a brand new GPU and run a modern kernel with an older linux-firmware snapshot amdgpu will fail probe and your framebuffer from EFI keeps working.