From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.82.179 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792523824; b=ieTwQanSyJAcP41VOTuXbgMutrPAZMGa0R8FJOYwMlngLlKSvnB1JGuusPU5i9MtJZ2u YYN+DYayAllprzAsivHZvK23aNDG/XDGuJgJySEt7kSVjxNaMaLpiD5zYcXG3F3aJBNz/ DUPzHCA3EJb7eHoAKwDC0U1j0JEOa5SGIqGSjylr1ZBNRQ/rkHlk5yulywbGsPqDA2COu 0mDgugH8N/vgnFTkdHuMolfXEss+FCrw3J5KgdKDjoAYwdbjJR2qiWcDF831WJdDLT2z7 f7D7HWbC0zDeWPSgPtlwIBdG9bbwm+DtNGKS5lGWG14xHKioThq4j2vCtPIDdreJIkw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792523824; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: Mime-Version:Content-Transfer-Encoding:Content-Type:Date:Message-Id: Cc:Subject:From:To:X-Mailer:References:In-Reply-To; bh=SWQgkR3Fjde1WyXhbg8hl8+vmi9aICLhiAaiA94/m88=; b=bRa4xyY3mamw/uZGOpl7Ni14Lg0Fu3/JQVo0xqfu6RDP8cBZRmvB2S3vfDvSiSSlbkoZ z3eif6O8rI6ktQl11WhZITK8Em1W5gaStt0FbflVEm3u+23a+eOyTSpXZGeaXxDgPdYVw ImrYzSMP9MI8BaNCz4bjuFN4tFQUhOWy9fa+9kQVXiJZFSiG7s8+U7RptZUxMfVhESqAK jswIHLwVomYjaxoYacd4DKBUWvOUh9/TSrR7pm0F1fBfgjoF/GqBkmOvVs/we4azld5Ze iCFyNMYI/N6Z3gzat7RJipas0lBM3eRi4nxzWl889fzZHIZH3XD+pDZCbWyPv8wdb+Q== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b="D/sVlb84"; arc=none smtp.remote-ip=74.125.82.179 Received: from mail-dy1-f179.google.com (mail-dy1-f179.google.com [74.125.82.179]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 034C5606A31F for ; Tue, 20 Oct 2026 19:17:03 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 034C5606A31F Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=D/sVlb84 Received: by mail-dy1-f179.google.com with SMTP id 5a478bee46e88-35159e0092aso441401eec.2 for ; Tue, 20 Oct 2026 12:17:03 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792523823; x=1793128623; darn=lists.linux.dev; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-type:content-transfer-encoding:mime-version:from:to:cc :subject:date:message-id:reply-to:content-type; bh=SWQgkR3Fjde1WyXhbg8hl8+vmi9aICLhiAaiA94/m88=; b=D/sVlb84QjWhhyq5gXPb3X9Ha6CPoa1ZjZoAyGhGYqi93VxSNFCtj5HvIpEVHBzWvB dYs1gkLJjhedanHqu6rIw5/CgjoDWp/VBUhvjzXlM/axsUi6vMSRza30X9kAyr4LNipT ObxHEwovWHtTlIP0bw453ul9xv038wsLMEuMoES7My2HTUEP8Nal4pM7OmF5WPP2sHJs JRF3kUDiVq4XCN7SlJfEjhHDJKeKsVSET8wzYe9X63biEma20apBWRZynMsa+qSe4s3B YXSzWev0q9I3XOsjgXQKV3S8fWyvH73i6fW9YE9IObD215nBUc6cB18kNvUUxjApY6UB xZlw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792523823; x=1793128623; h=in-reply-to:references:to:from:subject:cc:message-id:date :content-type:content-transfer-encoding:mime-version:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=SWQgkR3Fjde1WyXhbg8hl8+vmi9aICLhiAaiA94/m88=; b=onQtQIxNpIKJw9TlmGENYKLku/RTRh8S+UM0c/7JZsNt98XbUP+0AAV68CpRNlXbOu 58UtScFNPSha+M0mGm98GMxthrMD87lLbEryZP94y7VD9w5EjWOV2eQ0vjAQdaKHwN7N 9MUfLd4kv3HZu2qy+/QgeOkWOrdV2gsoBS6nwm4tKPf7Jl54G6RtmH0g75E3qSqqdpdC RW0yEQPjMb+kpsz4X3ZuSCvz07MkalkzbgYwCLdKSoAV+wCKRi9h3CtdWkXLBSY6tXaD JoasmmpmP+1tCs27alouf75bPDsrr4lnTDpxVEjU5ASgFVknSMtBshJmzibKasnK5lCd nCiQ== X-Forwarded-Encrypted: i=1; AKwUvBx9mvfhV1StvQjPd+YKycrZi9JPWQVcf7ptxMGju2+92HKl6HyOtPRgYi80A4PpyJwfj39HVNFyZ1/mHCpt@lists.linux.dev X-Gm-Message-State: AFq9FYJX7z7lwznv93uRTdWX/2xQjSGyw4bww4zDxcfl47bLCpwAOuqc gwnmlRJJPw6ntEt9GZ5vjoRuaILWeV86XWYB57cpN7yYkWMjca2WwC2H X-Gm-Gg: AYBFou2BYZOnjRvQbTy/j1CK/BoDt3j0oWnn2cMgjizegJfcesHUJPph/Q2UXyVf2cz mqPdts93XdkIiA4KSEAdH8y6hLCWvRl2wr6lFaFKkI0F2Mu3OVBFQiYz8hWa6UqU+h+NWxTQLxi Qnjo/GqTeoSgeivr06dzhuf6tMt+0b/esTs5D0ZW7oMGr1SFkK/t6+PUbwSURsAcZC7ajDo5x8Q rTRdwDML01R1mKmNUFfnuj4A+FxQLhYhjWe89gOheK0EEaDvzA05ptkG1AtLtNLLEeH22A3OC+3 F9VmtHX5DXLM5tELzbYX4yuEudsKxZRQeYDwHClDd3H8AX7jaH9of2DHxnI2/QF3d4xcsnKIuUT x0uPqgShLt9rh6mXiVpTeLB2O+6ldGaKEZVjXF/obdfxLRsaWaezMlO0GtZLzEhmsr/LDyjWSTL MYzUqGsbyIc2q6ocIPDKYpbdOKyTxERPlXOpOhYjHmNqH74Sym3hg2lKINsK8DvrIR8A== X-Received: by 2002:a05:701b:280f:b0:17f:641e:7f6b with SMTP id a92af1059eb24-1850fa07d82mr20915641c88.1.1792523822861; Tue, 20 Oct 2026 12:17:02 -0700 (PDT) Received: from localhost ([200.10.125.114]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-19035926035sm587423c88.1.2026.10.20.12.16.59 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 20 Oct 2026 12:17:02 -0700 (PDT) X-Mailing-List: linux-staging@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list Mime-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=UTF-8 Date: Tue, 20 Oct 2026 16:16:58 -0300 Message-Id: Cc: "Florian Fainelli" , "Broadcom internal kernel review list" , "Jai Luthra" , "Greg Kroah-Hartman" , "Stefan Wahren" , "Phil Elwell" , "Laurent Pinchart" , "Umang Jain" , "Kees Cook" , , , , , Subject: Re: [PATCH] platform/raspberrypi: vchiq: register bus at subsys_initcall From: "Gaston Gonzalez" To: "Martin Wetterwald" X-Mailer: aerc 0.20.0 References: <20261013131435.1454019-1-martin@wetterwald.eu> In-Reply-To: On Mon Oct 19, 2026 at 9:26 AM -03, Martin Wetterwald wrote: > On Sun, Oct 18, 2026 at 9:53=E2=80=AFPM Gaston Gonzalez wrote: > >> Running 'speaker-test -t wav -D plughw:1,0 -c 2' crash the system, so >> thinks seem not to be working with that interface. >> >> Im trying to debug what happens in that condition; I will need a couple >> of days I guess. So far, this is what I could check. >> >> Any feedback on the test or debugging would be appreciated. > > Hi Gaston, > Thanks for digging into this. > Hi Martin, > The patch only changes when the VCHIQ bus and driver are registered durin= g > boot. So it's enough to check these two cases to validate the patch: > - without my patch: dmesg shows the "unable to register with bus_type > 'vchiq-bus'" error, and bcm2835_hdmi is absent from /proc/asound/cards. > - with my patch: the error is gone and bcm2835_hdmi is present in > /proc/asound/cards. > Understood. Of the two cases, the second one is already tested if I'm not mistaken. I will check the 'without your patch' case first, and then I'll rerun the test with your patch. > (Since the Pi Zero has no Headphones jack, you need to test both cases wi= th > snd_bcm2835.enable_hdmi=3D1 in the command line. Otherwise the card never= shows > up, even when everything works.) > > Could you check these two cases? > Yes, will do. > > Testing that you can hear the sound going through bcm2835-audio is a full > functional test that goes even further than the patch: it does not only t= est > bus registration but also that the audio driver is working. > > On my side, without vc4-drm, I can successfully hear sound through both b= cm2835 > Headphones and bcm2835 HDMI: > > # aplay -l > **** List of PLAYBACK Hardware Devices **** > card 0: HDMI [bcm2835 HDMI], device 0: bcm2835 HDMI [bcm2835 HDMI] > [...] > card 0: HDMI [bcm2835 HDMI], device 1: IEC958 [IEC958] > [...] > card 1: Headphones [bcm2835 Headphones], device 0: bcm2835 > Headphones [bcm2835 Headphones] > [...] > > # speaker-test -D plughw:0,0 # (HDMI) > > # speaker-test -D plughw:1,0 # (Headphones, not on the Pi Zero) > > > If you still want to output sound through bcm2835_hdmi (optional): > > There can only be one owner of the HDMI port: either the firmware or the > kernel. > When the Raspberry Pi boots, the firmware first owns the HDMI and display= s a > rainbow splash. Then it launches Linux. > > There are 2 ways for the kernel to deal with the video output: > > 1) With vc4-drm (CONFIG_DRM_VC4), the kernel takes over the HDMI controll= er > from the firmware and handles everything itself (this is your case). > 2) With simple-framebuffer (CONFIG_DRM_SIMPLEDRM or CONFIG_FB_SIMPLE), th= e > kernel leaves the HDMI to the firmware and just writes pixels to a > memory area > (the framebuffer) set up by the firmware. > > I get a similar problem on my side when sending sound through bcm2835_hdm= i with > vc4-drm loaded: my screen shuts down (but the kernel is still alive). > It most likely comes from the firmware and the kernel both trying to driv= e the > same HDMI port: with vc4-drm, the kernel owns the HDMI controller, and th= e > firmware (which bcm2835-audio talks to through VCHIQ) is not supposed to = touch > it. > Ah ok, I did not know that. Thank you for the explanation. > A simple way to output sound through bcm2835_hdmi is to not use the vc4-d= rm > driver at all, and use simple-framebuffer if you still want a display. > > To remove vc4-drm: > - Do not compile the driver into the kernel (CONFIG_DRM_VC4=3Dn) or black= list the > module. > - Remove any vc4 overlay in config.txt file (e.g. remove dtoverlay=3Dvc4-= kms-v3d). > > To enable simple-framebuffer, use one of the two configs: > > CONFIG_DRM=3Dy > CONFIG_DRM_SIMPLEDRM=3Dy > CONFIG_DRM_FBDEV_EMULATION=3Dy > CONFIG_FRAMEBUFFER_CONSOLE=3Dy > > or, the older way: > > CONFIG_FB=3Dy > CONFIG_FB_SIMPLE=3Dy > CONFIG_FRAMEBUFFER_CONSOLE=3Dy > > (FRAMEBUFFER_CONSOLE=3Dy, and DRM_FBDEV_EMULATION in the DRM case, are on= ly > needed to see the boot messages on the screen, with console=3Dtty1 on the= command > line.) > > If you have remote access to your Pi Zero (either through network+SSH or > through serial console), you actually don't even need the simple-framebuf= fer: > you can just remove vc4-drm, and let the firmware display its rainbow spl= ash on > the HDMI port. > Then you can login to your Pi Zero through SSH for example and launch > speaker-test. > As long as the HDMI video output is active, it's enough for the sound to = be > able to go through, even if the image was not drawn by Linux. > > But again, this full functional test is optional. > Ok, I=E2=80=99ll test the patch first with the current configuration, then with simple-framebuffer enabled in a second step. Regards, Gaston > Regards, > Martin