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 F1D613EC81B for ; Thu, 3 Sep 2026 06:41:16 +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=1788417681; cv=none; b=uzsPQztvHxcvB95lgTLy+BwM1CpEBvSUZStsfClRs8rygmqv8AlPBD+PIF0H0gTd3OhGF3JL+8XWMZDpp7HdrphAkfqgD6ptdMl2Nv24CXFxfZXd2CDCqFV5Vl0w7ySMDqRLJJXoS+cam9okwvxKD8p4CW6pn7EoA3Ts3xqCSk0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788417681; c=relaxed/simple; bh=SfKssssLeWKCFofjWMwwEAMkU33TViZYopeZNDqTzLM=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=eq0ZpMsW0uEPANdBI5M7A5YHTrtteVAqFKyNKRZHc56ftIreY9HjwSzBulhzhW4k2k3E6d3TwFgNcqUlP/BNGUkU0swVOFT3+PW1XMEa2+kUcxEu0lEwNeHijaUK0+FzKcjrYUdMjZQouYzYz6voVx+xonOptxtToPzbOCoz5Jw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=W7CIxV9a; 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="W7CIxV9a" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 062EB1F000E9; Thu, 3 Sep 2026 06:41:14 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788417675; bh=kDtL7yEn2fBaNyWvwOyoAmPEDlgixjrIr5JhIW1ednI=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=W7CIxV9aVq75ejoXWJXtSj4dR4vf5PQEJUnsNWhLjt7V9KQMCO1N+Ho7XexROlfET uZiMN7khZ/B/A8JlXQ5L2/0HRR8mL0ZxN72K1WpAAoApcbTCx0d3yCd4UvbwM52zNv 0K9wFRrhK66wTtQIAUbTmqr9pxJpPRMvV1G+33VIlge4IukjAwoSFUkVBXF9waikOz BI0tYVfHyWvkJSf+iCTwPOOc+vOIAJ4K1SWOU7URPrli/0IdyqG1l5nSc1gEFq0vHu vN3MRpXrMo7bEEpXPxXOAAet6C84RQqgL2sCKB7YPJzTbvvDm6Qji8JAWVwb58Uma+ 5/vH7uvuPA2KQ== From: sashiko-bot@kernel.org Subject: Re: PCI: bridge window undersized when child bridge windows are larger than their alignment (regression since 3958bf16e2fe, v7.0) Reply-To: sashiko-reviews@lists.linux.dev To: "Nikolas Joshua Britton" Cc: linux-pci@vger.kernel.org In-Reply-To: <20260903063124.9316-1-nbritton@exabit.io> References: <20260903063124.9316-1-nbritton@exabit.io> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 03 Sep 2026 06:41:14 +0000 Message-Id: <20260903064115.062EB1F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > Hi, >=20 > On a Mac Pro 7,1 with two Radeon Pro Vega II Duo cards, enabling 32 GB > Resizable BARs leaves exactly half the GPU dies with no BAR at all. The > shared root-port prefetchable window is sized as the plain sum of its two > child bridge windows, but each child secretly requires a 32 GB-aligned > start, so the window that gets allocated is ~32 GB smaller than the span > that is actually needed. The second child of each pair loses, > deterministically. >=20 > There is 1 TiB of free space in the host bridge's _CRS window, so this is > not address-space exhaustion. >=20 > This is a regression. On the same machine, with the same script > (resize-amdgpu-bars, https://github.com/exabit-io/resize-amdgpu-bars, > [ ... ] > - lspci -vvnn from the v7.0.12 + patch boot >=20 >=20 > #regzbot introduced: 3958bf16e2fe >=20 Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260903063124.9316= -1-nbritton@exabit.io?part=3D1