From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CE9AD42E004 for ; Mon, 6 Jul 2026 12:37:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783341458; cv=none; b=PjLeWHZAJPhRa29MwttO4FIi9J6fVPtE/buBJTy7lQuO9A04skJpp5J7XDRAjfp7+/pUtKaqfjsDtFsTGINpT1UrUCKAVwyNhdMpd5TdOU1XmZ5Yy2n2y4t2aByndkVR4y95/AsFWrG/122A7Djjadv2/rdV00fVZRItdH8hKzs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1783341458; c=relaxed/simple; bh=A+TzSzTWMVwGu/4O/ST/AhSChLuRtfENjmPqTz2jWfI=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=LMKwgPWivWJR3C14KTnpTvP6g5q0I2R/FrnuKbATLDiRqoagztLo6cC2NXtv8nsEzyxYGHGPjmUYf7FVBCdB5AAs56sANBKi5y6d0Klp/tFaoktbi+n2xczw1bOW8/PYJTHAEzw+bn4YMoGgLh4rKv0cURQM5WsEsRecDiAElYo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=lf20jMnq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="lf20jMnq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7AE8E1F00A3A; Mon, 6 Jul 2026 12:37:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1783341455; bh=Dkwciwub+LC3jtmcGo18YxxwOqPtztOBGVcQ1TkgDsk=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=lf20jMnqvCEOW4zQrrQfnQ/ToPd3XNy/+FgrjoiQ5zhllV6vJoOxE8QePM569Dcze h3kDWCSchOBOl6dyraQyQQ9B2SAhVnbxlEktbIPGItMWyebpp8tFnX64JVyAoMGays gPXAzlwxPZffMee8OuIH9ufwFOmcRrBKDTyB1GABf2rPy+d6UJmxRA/VXyGnvgmTOF Noci46RsqLtuTODX8gZ6FMd1EZf6XXM9Dd8uFGpR413LYO4Aaf1fNR8H535JsvcP8g O9tgGoxLPTm1/nc4N9keBENnF+0en93FiPXiNofFEPWnBqNmzt8yKQARlPvpCoSNwb lfy7jWmathr+g== From: sashiko-bot@kernel.org Subject: Re: [RFC PATCH] PCI: Get the hotplug bridge window sizes from DT Reply-To: sashiko-reviews@lists.linux.dev To: "Manivannan Sadhasivam" Cc: linux-pci@vger.kernel.org In-Reply-To: <20260706123133.545104-1-manivannan.sadhasivam@oss.qualcomm.com> References: <20260706123133.545104-1-manivannan.sadhasivam@oss.qualcomm.com> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Mon, 06 Jul 2026 12:37:34 +0000 Message-Id: <20260706123735.7AE8E1F00A3A@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Most of the PCI hotplug bridges used in Devicetree platforms do not have > their bridge windows populated by firmware. So the PCI core allocates the > bridge windows based on the requirements below: >=20 > 1. Total size needed by the downstream devices > 2. Default size (2MiB for MMIO, 256 bytes for IO) if no devices are > available during the initial bus scan > 3. Command line params like hpmemsize etc... >=20 > If no devices are available during the initial bus scan, then the PCI core > allocates the default conservative 2MiB MMIO bridge windows. But this size > sometimes becomes insufficient when a BAR hungry device like a GPU gets > plugged in later. So users have to resort to command line params to > increase the window sizes. But this is very inconvenient and causes a lot > of pain in distro integration. >=20 > To address this issue, parse the 'ranges' property from the bridge DT node > (if available) and use the sizes for each bridge window. This works well > because the 'ranges' property is already allowed by the DT binding for PCI > bridges and it lets system designers pre-define the hotplug bridge window > size requirements in firmware. >=20 > The DT derived sizes are applied as the additional (hotplug) reservation = for > each window. Command line parameters (hpmemsize etc...) continue to take > precedence over DT. >=20 > Signed-off-by: Manivannan Sadhasivam Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260706123133.5451= 04-1-manivannan.sadhasivam@oss.qualcomm.com?part=3D1