From patchwork Sat Apr 30 13:41:46 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mauro Carvalho Chehab X-Patchwork-Id: 12833260 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 7C9E8C433EF for ; Sat, 30 Apr 2022 13:41:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242032AbiD3NpS (ORCPT ); Sat, 30 Apr 2022 09:45:18 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43728 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234800AbiD3NpR (ORCPT ); Sat, 30 Apr 2022 09:45:17 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 04EBB3A18A; Sat, 30 Apr 2022 06:41:55 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 9D18E6091F; Sat, 30 Apr 2022 13:41:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 05609C385AA; Sat, 30 Apr 2022 13:41:53 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1651326114; bh=z1ShzoCSkbQb+bOpuaiBtOfCObZ5xV/5jCkA52fVM7U=; h=From:To:Cc:Subject:Date:From; b=ZSoiPmfwpPthXwwLa+SgKEi3DzH2Y1E+GN8PH8yc8mRVbjar4q05Gt45Z5GnuOC9r DTQR2PrUvyCR5hjBBVFXEkXT/24eZiI/31Qzl2M+9U+jdclLfZJ4cJOSqO/0zXB3fi /JQQCltMWzh4hCzbuZ49YlcTU/AynOFfg0PGeINz91OtWxxI3MnYaomVQO8VumZTZI JOj8/uyj+4pj+2nnTnlWrLoKjlTWhjC+PcukaXUpFLgVzNGNysenUz6lb4icrnpUMp loucqMnkOtEc6nfxhIT7qckU12c5SF85dy/WmK2mbaQCzhDuwYIkXc9z9/FXiTII/Q 4GiqNWH0i7hZw== Received: from mchehab by mail.kernel.org with local (Exim 4.94.2) (envelope-from ) id 1nknM6-001nsd-HX; Sat, 30 Apr 2022 14:41:50 +0100 From: Mauro Carvalho Chehab To: Luis Chamberlain Cc: Mauro Carvalho Chehab , mauro.chehab@linux.intel.com, Greg KH , intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, Lucas De Marchi , Kai Vehmanen , Pierre-Louis Bossart , Jaroslav Kysela , Takashi Iwai , alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, linux-modules@vger.kernel.org, Daniel Vetter , David Airlie Subject: [PATCH v3 0/2] Let userspace know when snd-hda-intel needs i915 Date: Sat, 30 Apr 2022 14:41:46 +0100 Message-Id: X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 Precedence: bulk List-ID: Currently, kernel/module annotates module dependencies when request_symbol is used, but it doesn't cover more complex inter-driver dependencies that are subsystem and/or driver-specific. In the case of hdmi sound, depending on the CPU/GPU, sometimes the snd_hda_driver can talk directly with the hardware, but sometimes, it uses the i915 driver. When the snd_hda_driver uses i915, it should first be unbind/rmmod, as otherwise trying to unbind/rmmod the i915 driver cause driver issues, as as reported by CI tools with different GPU models: https://intel-gfx-ci.01.org/tree/drm-tip/IGT_6415/fi-tgl-1115g4/igt@core_hotunplug@unbind-rebind.html https://intel-gfx-ci.01.org/tree/drm-tip/CI_DRM_11495/bat-adlm-1/igt@i915_module_load@reload.html In the past, just a few CPUs were doing such bindings, but this issue now applies to all "modern" Intel CPUs that have onboard graphics, as well as to the newer discrete GPUs. With the discrete GPU case, the HDA controller is physically separate and requires i915 to power on the hardware for all hardware access. In this case, the issue is hit basicly 100% of the time. With on-board graphics, i915 driver is needed only when the display codec is accessed. If i915 is unbind during runtime suspend, while snd-hda-intel is still bound, nothing bad happens, but unbinding i915 on other situations may also cause issues. So, add support at kernel/modules to allow snd-hda drivers to properly annotate when a dependency on a DRM driver dependencies exists, and add a call to such new function at the snd-hda driver when it successfully binds into the DRM driver. This would allow userspace tools to check and properly remove the audio driver before trying to remove or unbind the GPU driver. It should be noticed that this series conveys the hidden module dependencies. Other changes are needed in order to allow removing or unbinding the i915 driver while keeping the snd-hda-intel driver loaded/bound. With that regards, there are some discussions on how to improve this at alsa-devel a while back: https://mailman.alsa-project.org/pipermail/alsa-devel/2021-September/190099.html So, future improvements on both in i915 and the audio drivers could be made. E.g. with discrete GPUs, it's the only codec of the card, so it seems feasible to detach the ALSA card if i915 is bound (using infra made for VGA switcheroo), but, until these improvements are done and land in upstream, audio drivers needs to be unbound if i915 driver goes unbind. Yet, even if such fixes got merged, this series is still needed, as it makes such dependencies more explicit and easier to debug. PS.: This series was generated against next-20220428. --- v3: minor fixes: - fixed a checkpatch warning; - use a single line for the new function prototype. v2: - the dependencies are now handled directly at try_module_get(). Mauro Carvalho Chehab (2): module: update dependencies at try_module_get() ALSA: hda - identify when audio is provided by a video driver include/linux/module.h | 4 +++- kernel/module/main.c | 33 +++++++++++++++++++++++++++++++-- sound/hda/hdac_component.c | 2 +- 3 files changed, 35 insertions(+), 4 deletions(-)