From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D8DFB26CE2A; Thu, 24 Jul 2025 18:41:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753382500; cv=none; b=jsKZbllEe/TZatBzXw1xXnZg2Keb76xMahTmaC4XkCUgBaS8de+3Z5yPXiVUgziIPacG03J9a7J/3OMtBA3y0L+vMPiK90pA7rPFt7a7RPzQsWEeTSnbVXsxXIG7vdjQtSI5OvmUYgvZoqgjBnYEAm3eHnRFQ4kWwZpH2EnJzPA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1753382500; c=relaxed/simple; bh=IrAJV8qmnHwIF1sbkngYGyar5n5RP/TH+eX8V1mvAyQ=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=lG6t81Pp2ykgChYpq8dqZd5Wzf76tb5PjzMOTKDh2GIeYN/DBhTEP5FJ+yf8p1APRcDd1D/XKuPLIA9ublyWFF4PrXyZUqLF8wunDS0DNS9r3+ysQHmB2JFXMDwLzC/7Xdlk3OWWoeRA9uHsY9BQZ8BWAR8qBBVJ5AvO9SPbRRY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eTEI8MNE; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eTEI8MNE" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 16D57C4CEF1; Thu, 24 Jul 2025 18:41:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1753382498; bh=IrAJV8qmnHwIF1sbkngYGyar5n5RP/TH+eX8V1mvAyQ=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=eTEI8MNEcMLUiF9MvBHkxWp18WyWAhuc5fcBUfimgY/kfxfBF2v0Xu0Wn5c8UBGTU Dl5S8WhUNQJZe7UBmc+zpyLO6k0ytQJcQHQeC1VDQSV0DbXu0SPivY/IvbnsgLjfY4 xyV3DvXUavRxjsuIRd7XmIu/TndUSNQa3mT6I5l/SlKm865bJsOcg3a5OzG52eGKLC nmgXctPiTouYH3nsCIbaaFbtC3AJnp0zaCJWQCkOGuj1wWE+/Ugy1aNRYpqYyJKJf6 mlCGIwtJF+JLqCgrs+lAZo7DH3pmPIGyj0J67jCMnmmTNvJgg93ynFD+UBome6K4hj Tm1/DAY78iGSw== Message-ID: <75172a8b-c398-4646-86d6-5912cad9a48c@kernel.org> Date: Thu, 24 Jul 2025 13:41:33 -0500 Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v9 0/9] Adjust fbcon console device detection To: Bjorn Helgaas Cc: David Airlie , Bjorn Helgaas , Alex Deucher , =?UTF-8?Q?Christian_K=C3=B6nig?= , Simona Vetter , Lukas Wunner , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Woodhouse , Lu Baolu , Joerg Roedel , Will Deacon , Robin Murphy , Alex Williamson , Jaroslav Kysela , Takashi Iwai , "open list:DRM DRIVERS" , open list , "open list:INTEL IOMMU (VT-d)" , "open list:PCI SUBSYSTEM" , "open list:VFIO DRIVER" , "open list:SOUND" , Daniel Dadap , Mario Limonciello References: <20250724183623.GA2947098@bhelgaas> Content-Language: en-US From: Mario Limonciello In-Reply-To: <20250724183623.GA2947098@bhelgaas> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 7/24/2025 1:36 PM, Bjorn Helgaas wrote: > On Thu, Jul 17, 2025 at 03:56:58PM -0500, Bjorn Helgaas wrote: >> On Thu, Jul 17, 2025 at 12:38:03PM -0500, Mario Limonciello wrote: >>> From: Mario Limonciello >>> >>> Systems with more than one GPU userspace doesn't know which one to be >>> used to treat as primary. The concept of primary is important to be >>> able to decide which GPU is used for display and which is used for >>> rendering. If it's guessed wrong then both GPUs will be kept awake >>> burning a lot of power. >>> >>> Historically it would use the "boot_vga" attribute but this isn't >>> present on modern GPUs. >>> >>> This series started out as changes to VGA arbiter to try to handle a case >>> of a system with 2 GPUs that are not VGA devices and avoid changes to >>> userspace. This was discussed but decided not to overload the VGA arbiter >>> for non VGA devices. >>> >>> Instead move the x86 specific detection of framebuffer resources into x86 >>> specific code that the fbcon can use to properly identify the primary >>> device. This code is still called from the VGA arbiter, and the logic does >>> not change there. To avoid regression default to VGA arbiter and only fall >>> back to looking up with x86 specific detection method. >>> >>> In order for userspace to also be able to discover which device was the >>> primary video display device create a new sysfs file 'boot_display'. >>> >>> A matching userspace implementation for this file is available here: >>> Link: https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/merge_requests/39 >>> Link: https://gitlab.freedesktop.org/xorg/xserver/-/merge_requests/2038 >>> >>> Dave Airlie has been pinged for a comment on this approach. >>> Dave had suggested in the past [1]: >>> >>> " >>> But yes if that doesn't work, then maybe we need to make the boot_vga >>> flag mean boot_display_gpu, and fix it in the kernel >>> " >>> >>> This was one of the approached tried in earlier revisions and it was >>> rejected in favor of creating a new sysfs file (which is what this >>> version does). >>> >>> It is suggested that this series merge entirely through the PCI tree. >>> >>> Link: https://gitlab.freedesktop.org/xorg/lib/libpciaccess/-/merge_requests/37#note_2938602 [1] >>> >>> v9: >>> * Add more to cover letter >>> * Add bug link to last patch >>> * Update commit message for last patch >>> * Update boot_display documentation description >>> >>> Mario Limonciello (9): >>> PCI: Add helper for checking if a PCI device is a display controller >>> vfio/pci: Use pci_is_display() >>> vga_switcheroo: Use pci_is_display() >>> iommu/vt-d: Use pci_is_display() >>> ALSA: hda: Use pci_is_display() >>> Fix access to video_is_primary_device() when compiled without >>> CONFIG_VIDEO >>> PCI/VGA: Replace vga_is_firmware_default() with a screen info check >>> fbcon: Use screen info to find primary device >>> PCI: Add a new 'boot_display' attribute >>> >>> Documentation/ABI/testing/sysfs-bus-pci | 9 +++++ >>> arch/parisc/include/asm/video.h | 2 +- >>> arch/sparc/include/asm/video.h | 2 ++ >>> arch/x86/include/asm/video.h | 2 ++ >>> arch/x86/video/video-common.c | 17 ++++++++- >>> drivers/gpu/vga/vga_switcheroo.c | 2 +- >>> drivers/iommu/intel/iommu.c | 2 +- >>> drivers/pci/pci-sysfs.c | 46 +++++++++++++++++++++++++ >>> drivers/pci/vgaarb.c | 31 +++-------------- >>> drivers/vfio/pci/vfio_pci_igd.c | 3 +- >>> include/linux/pci.h | 15 ++++++++ >>> sound/hda/hdac_i915.c | 2 +- >>> sound/pci/hda/hda_intel.c | 4 +-- >>> 13 files changed, 102 insertions(+), 35 deletions(-) >> >> Applied to pci/boot-display for v6.17, thanks! > > I kept the pci_is_display() changes but deferred the following for now: > > Fix access to video_is_primary_device() when compiled without CONFIG_VIDEO > PCI/VGA: Replace vga_is_firmware_default() with a screen info check > fbcon: Use screen info to find primary device > PCI: Add a new 'boot_display' attribute > > I think the boot_display attribute isn't quite baked yet and I don't > want to add something when it looks like we're immediately going to > change the implementation and maybe the sysfs location. > > Bjorn Thanks for the update. The patch moving to DRM does have an Acked-by. At this point do you think there is still a shot at a squashed/rebased version of those for 6.17, or should I rebase and submit the outcome for discussion targeting 6.18 after the merge window?