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=-12.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=unavailable 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 8C45AC433B4 for ; Tue, 13 Apr 2021 08:24:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 66BE261369 for ; Tue, 13 Apr 2021 08:24:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229446AbhDMIY4 (ORCPT ); Tue, 13 Apr 2021 04:24:56 -0400 Received: from mupuf.org ([167.71.42.210]:49766 "EHLO mupuf.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229379AbhDMIYy (ORCPT ); Tue, 13 Apr 2021 04:24:54 -0400 Received: from [IPv6:2a01:4b00:86b9:100:9ede:1593:85ef:7eda] (unknown [IPv6:2a01:4b00:86b9:100:9ede:1593:85ef:7eda]) by Neelix.spliet.org (Postfix) with ESMTPSA id 594CDF200CA; Tue, 13 Apr 2021 09:24:25 +0100 (BST) DKIM-Filter: OpenDKIM Filter v2.11.0 Neelix.spliet.org 594CDF200CA DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=spliet.org; s=default; t=1618302265; bh=ZSMMJNLLy7PJx+gCafIgpvXbgVN92rwCc0aHNrG6QGM=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=Z+dN4zNjcVZ1d8H4EquYXwVMarcx81SBON/bGIMNLp5nHdirj04lPuP157bQDyG2k bTM3vZIflX4clTcDHLF8ss+vQdjJ10O/gq1jNWCR2G2mZCzgoz6d7DN8Im+tMl+RKo B8lS/SCb5Ko8wkdeJ8qm7lzKorn7DRCFkfX4DRPs= Subject: Re: [Nouveau] [PATCH v2] ALSA: hda: Continue to probe when codec probe fails To: Karol Herbst Cc: Aaron Plattner , Lukas Wunner , Kai-Heng Feng , "moderated list:SOUND" , Kai Vehmanen , Takashi Iwai , nouveau , Pierre-Louis Bossart , tiwai@suse.com, Alex Deucher , Alan Stern , Mike Rapoport , Linux PCI , Bjorn Helgaas , Jaroslav Kysela , open list References: <20210410192314.GB16240@wunner.de> <81b2a8c7-5b0b-b8fa-fbed-f164128de7a3@nvidia.com> <8d358110-769d-b984-d2ec-825dc2c3d77a@spliet.org> From: Roy Spliet Message-ID: <7edf5ed4-40ea-1cee-83e4-6e9b307b432a@spliet.org> Date: Tue, 13 Apr 2021 09:24:24 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit X-Virus-Scanned: clamav-milter 0.103.2 at Neelix X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Op 13-04-2021 om 01:10 schreef Karol Herbst: > On Mon, Apr 12, 2021 at 9:36 PM Roy Spliet wrote: >> >> Hello Aaron, >> >> Thanks for your insights. A follow-up query and some observations in-line. >> >> Op 12-04-2021 om 20:06 schreef Aaron Plattner: >>> On 4/10/21 1:48 PM, Roy Spliet wrote: >>>> Op 10-04-2021 om 20:23 schreef Lukas Wunner: >>>>> On Sat, Apr 10, 2021 at 04:51:27PM +0100, Roy Spliet wrote: >>>>>> Can I ask someone with more >>>>>> technical knowledge of snd_hda_intel and vgaswitcheroo to brainstorm >>>>>> about >>>>>> the possible challenges of nouveau taking matters into its own hand >>>>>> rather >>>>>> than keeping this PCI quirk around? >>>>> >>>>> It sounds to me like the HDA is not powered if no cable is plugged in. >>>>> What is reponsible then for powering it up or down, firmware code on >>>>> the GPU or in the host's BIOS? >>>> >>>> Sometimes the BIOS, but definitely unconditionally the PCI quirk code: >>>> https://github.com/torvalds/linux/blob/master/drivers/pci/quirks.c#L5289 >>>> >>>> (CC Aaron Plattner) >>> >>> My basic understanding is that the audio function stops responding >>> whenever the graphics function is powered off. So the requirement here >>> is that the audio driver can't try to talk to the audio function while >>> the graphics function is asleep, and must trigger a graphics function >>> wakeup before trying to communicate with the audio function. >> >> I believe that vgaswitcheroo takes care of this for us. >> > > yeah, and also: why would the driver want to do stuff? If the GPU is > turned off, there is no point in communicating with the audio device > anyway. The driver should do the initial probe and leave the device be > unless it's actively used. Also there is no such thing as "use the > audio function, but not the graphics one" > >>> I think >>> there are also requirements about the audio function needing to be awake >>> when the graphics driver is updating the ELD, but I'm not sure. >>> > > well, it's one physical device anyway, so technically the audio > function is powered on. > >>> This is harder on Windows because the audio driver lives in its own >>> little world doing its own thing but on Linux we can do better. >>> >>>>> Ideally, we should try to find out how to control HDA power from the >>>>> operating system rather than trying to cooperate with whatever firmware >>>>> is doing. If we have that capability, the OS should power the HDA up >>>>> and down as it sees fit. >>> >>> After system boot, I don't think there's any firmware involved, but I'm >>> not super familiar with the low-level details and it's possible the >>> situation changed since I last looked at it. >>> >>> I think the problem with having nouveau write this quirk is that the >>> kernel will need to re-probe the PCI device to notice that it has >>> suddenly become a multi-function device with an audio function, and >>> hotplug the audio driver. I originally looked into trying to do that but >>> it was tricky because the PCI subsystem didn't really have a mechanism >>> for a single-function device to become a multi-function device on the >>> fly and it seemed easier to enable it early on during bus enumeration. >>> That way the kernel sees both functions all the time without anything >>> else having to be special about this configuration. > > Well, we do have this pci/quirk.c thing, no? Nouveau does flip the > bit, but I am actually not sure if that's even doing something > anymore. Maybe in the runtime_resume case it's still relevant but not > sure _when_ DECLARE_PCI_FIXUP_CLASS_RESUME_EARLY is triggered, it does > seem to be called even in the runtime_resume case though. > >> >> Right, so for a little more context: a while ago I noticed that my >> laptop (lucky me, Asus K501UB) has a 940M with HDA but no codec. Seems >> legit, given how this GPU has no displays attached; they're all hooked >> up to the Intel integrated GPU. That threw off the snd_hda_intel >> mid-probe, and as a result didn't permit runpm, keeping the entire GPU, >> PCIe bus and thus the CPU package awake. A bit of hackerly later we >> decided to continue probing without a codec, and now my laptop is happy, >> but... >> A new problem popped up with several other NVIDIA GPUs that expose their >> HDA subdevice, but somehow its inaccessible. Relevant lines from a >> users' log: >> >> [ 3.031222] MXM: GUID detected in BIOS >> [ 3.031280] ACPI BIOS Error (bug): AE_AML_PACKAGE_LIMIT, Index >> (0x000000003) is beyond end of object (length 0x0) (20200925/exoparg2-393) >> [ 3.031352] ACPI Error: Aborting method \_SB.PCI0.GFX0._DSM due to >> previous error (AE_AML_PACKAGE_LIMIT) (20200925/psparse-529) >> [ 3.031419] ACPI: \_SB_.PCI0.GFX0: failed to evaluate _DSM (0x300b) >> [ 3.031424] ACPI Warning: \_SB.PCI0.GFX0._DSM: Argument #4 type >> mismatch - Found [Buffer], ACPI requires [Package] (20200925/nsarguments-61) >> [ 3.031619] pci 0000:00:02.0: optimus capabilities: enabled, status >> dynamic power, >> [ 3.031667] ACPI BIOS Error (bug): AE_AML_PACKAGE_LIMIT, Index >> (0x000000003) is beyond end of object (length 0x0) (20200925/exoparg2-393) >> [ 3.031731] ACPI Error: Aborting method \_SB.PCI0.GFX0._DSM due to >> previous error (AE_AML_PACKAGE_LIMIT) (20200925/psparse-529) >> [ 3.031791] ACPI Error: Aborting method \_SB.PCI0.PEG0.PEGP._DSM due >> to previous error (AE_AML_PACKAGE_LIMIT) (20200925/psparse-529) >> [ 3.031856] ACPI: \_SB_.PCI0.PEG0.PEGP: failed to evaluate _DSM (0x300b) >> [ 3.031859] ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type >> mismatch - Found [Buffer], ACPI requires [Package] (20200925/nsarguments-61) > > If I am not wrong we are calling the _DSM method inside nouveau when > doing runpm on pre _PR3 systems. As this is all very vendor specific, > we might be doing something incorrectly. > >> [ 3.032058] pci 0000:01:00.0: optimus capabilities: enabled, status >> dynamic power, >> [ 3.032061] VGA switcheroo: detected Optimus DSM method >> \_SB_.PCI0.PEG0.PEGP handle >> [ 3.032323] checking generic (d0000000 410000) vs hw (f6000000 1000000) >> [ 3.032325] checking generic (d0000000 410000) vs hw (e0000000 10000000) >> [ 3.032326] checking generic (d0000000 410000) vs hw (f0000000 2000000) >> [ 3.032410] nouveau 0000:01:00.0: NVIDIA GK107 (0e71f0a2) >> [ 3.042385] nouveau 0000:01:00.0: bios: version 80.07.a0.00.11 >> --- snip --- >> [ 8.951478] snd_hda_intel 0000:01:00.1: can't change power state from >> D3cold to D0 (config space inaccessible) >> [ 8.951509] snd_hda_intel 0000:01:00.1: can't change power state from >> D3hot to D0 (config space inaccessible) > > This is actually a little bad, because it means that the device > doesn't come back up from D3. It's a bit weird it's D3cold and D3hot > in the messages, but maybe the device just takes quite some time to > wake up. But it does look like the device gets woken up. > >> [ 8.951608] snd_hda_intel 0000:01:00.1: Disabling MSI >> [ 8.951621] snd_hda_intel 0000:01:00.1: Handle vga_switcheroo audio >> client >> [ 8.952461] snd_hda_intel 0000:00:1b.0: bound 0000:00:02.0 (ops >> i915_audio_component_bind_ops [i915]) >> [ 8.952642] snd_hda_intel 0000:01:00.1: number of I/O streams is 30, >> forcing separate stream tags >> >> Now I don't know what's going on, but the snd_hda_intel messages are >> ominous. And so are the ACPI warnings. But I don't know how much these >> two are related. >> > > What is the actual problem though? Seems like everything is fine > despite those messages. The problem, as stated a few e-mails earlier, is that the HDA errors currently prevent snd_hda_intel from properly probing the device and registering it with vgaswitcheroo. As a result, the GPU always stays in DynPwr rather than DynOff even when it's unused, keeping the PCIe bus and the CPU package powered. Basically burning through a charged battery a lot quicker than need be. If we go back a mile on the e-mail thread, I think the problem was narrowed down to snd_hda_intel reading an invalid codec mask on the config space, and using it anyway. That being said, I believe there are also reports of users that don't get HDMI audio unless the cable was plugged in at boot-time, with similar messages in their logs. The codec might in such cases be hiding themselves until a cable is plugged in? @Aaron Plattner: does that latter observation sound right to you? > >> You say that it is desirable to switch on HDA at boot-time because the >> PCI subsystem doesn't play nicely with changing a device to >> multi-function. That rules out the option of only enabling the HDA >> device once a cable is plugged in. Are there any other trap doors that > > yeah, we can absolutely not do that. We do quirk the device to put the > GPU into multi function state asap and the intel_hda_snd driver should > deal with it. > >> snd_hda_intel needs to navigate around to make this work fault free on >> all hardware, such as: >> - Codecs not revealing themselves until a display is plugged in, >> requiring perhaps a "codec reprobe" and "codec remove" event from >> nouveau/rm to snd_hda_intel, > > we could trigger the reprobe from within nouveau as we are dealing > with display hotplug events anyway. Right. Are there situations where nouveau needs to? Or is this a misunderstanding of the problem from my end? > >> - Borked BIOSes just blindly assigning the MMIO space of the HDA device >> to another device, or nothing at all, > > that exists? *sigh* > >> - ... other things that might give any of us nightmares and heart burn? >> > > hopefully there are none :p > >> Thanks! >> >> Roy >> >>> >>> -- Aaron >>> >>>>> Thanks, >>>>> >>>>> Lukas >> >