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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11D05C4332F for ; Fri, 22 Oct 2021 19:13:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F16C061056 for ; Fri, 22 Oct 2021 19:13:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234184AbhJVTPc (ORCPT ); Fri, 22 Oct 2021 15:15:32 -0400 Received: from mga01.intel.com ([192.55.52.88]:19048 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233732AbhJVTPW (ORCPT ); Fri, 22 Oct 2021 15:15:22 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10145"; a="252874016" X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="252874016" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga101.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Oct 2021 12:13:01 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,173,1631602800"; d="scan'208";a="495799065" Received: from stinkbox.fi.intel.com (HELO stinkbox) ([10.237.72.171]) by orsmga008.jf.intel.com with SMTP; 22 Oct 2021 12:12:58 -0700 Received: by stinkbox (sSMTP sendmail emulation); Fri, 22 Oct 2021 22:12:57 +0300 Date: Fri, 22 Oct 2021 22:12:57 +0300 From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= To: Javier Martinez Canillas Cc: linux-kernel@vger.kernel.org, Thomas Zimmermann , Peter Robinson , Neal Gompa , Daniel Vetter , David Airlie , Maarten Lankhorst , Maxime Ripard , dri-devel@lists.freedesktop.org Subject: Re: [RFC PATCH] drm/aperture: Add param to disable conflicting framebuffers removal Message-ID: References: <20211022144040.3418284-1-javierm@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20211022144040.3418284-1-javierm@redhat.com> X-Patchwork-Hint: comment Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Oct 22, 2021 at 04:40:40PM +0200, Javier Martinez Canillas wrote: > The simpledrm driver allows to use the frame buffer that was set-up by the > firmware. This gives early video output before the platform DRM driver is > probed and takes over. > > But it would be useful to have a way to disable this take over by the real > DRM drivers. For example, there may be bugs in the DRM drivers that could > cause the display output to not work correctly. > > For those cases, it would be good to keep the simpledrm driver instead and > at least get a working display as set-up by the firmware. > > Let's add a drm.remove_fb boolean kernel command line parameter, that when > set to false will prevent the conflicting framebuffers to being removed. > > Since the drivers call drm_aperture_remove_conflicting_framebuffers() very > early in their probe callback, this will cause the drivers' probe to fail. Why is that better than just modprobe.blacklisting those drivers? -- Ville Syrjälä Intel