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 B40A7470456 for ; Fri, 2 Oct 2026 09:18:56 +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=1790932737; cv=none; b=s6iw9TCXGWayZ4O2KcRna2ptgsCv5O0Dguang1rkjVVPXMy/y3Rds7KNdPDtSc17nvXrOxB38wY9wgtKgDGS5yLp7aDRs1ElYBX4SOKXoqFLJ72uTahZdtJGJ38/rxDJhiq8vSjFjgpNg3k/av0NrR8MpDerWPN7VODyqEYdayA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790932737; c=relaxed/simple; bh=zQL2EPvMfmomBsZEsdKKjBntQy2iyaPiZB2OcBDEMU0=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=kheZEIfP0+T7ibPXdMMtUv+itXwGXrtV52j3cloKFJiMfXmLx7FH3arLDkWzbxOIs7e/prjIb7SQCU4S8qdA/e1KijOPgUSfHrInchNe+Q3hIHccTRXg3Cl6TVSGwF8FPP4Y/l4fytiS3UYK3jd5AIlUZC0NdAWrbno57VkowxA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GiMJsSAj; 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="GiMJsSAj" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 55CD51F00898; Fri, 2 Oct 2026 09:18:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1790932736; bh=zQL2EPvMfmomBsZEsdKKjBntQy2iyaPiZB2OcBDEMU0=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=GiMJsSAjsiQHUGrFWLm4Vk3V7Emt1XgpIoaScbyLnGGqy+S6DFBy+AmeJnlIt8vF9 sNYMbtcsPFDLO0vKnp2fI6QuTeL5S7AlgEKLvHjMCZyrEa8n8oPtW3Hn9gW9irfvYO H4thFBCyflQeufudnhGhcW+7d6GbSJJAkPFw5E8z65DhwIpwFRuXnjD/pCNQvbwKKL h0ifs09nouoFCcfCG5ae1Dk176ktVXhgsgWIgrSu1lKmmQRloVlaATqb7XDRZR2uem rzZiwQB1EIBgihwFpvwnfEIolzwRZAUX9L6TYOz8KHwTO+de3Jey3QYUX6scjXhW1u 7024MDHfVq8QQ== From: sashiko-bot@kernel.org Subject: Re: [PATCH v2 2/2] PCI: Set RCB only when the Root Port has it set Reply-To: sashiko-reviews@lists.linux.dev To: "Stefan Roese" Cc: linux-pci@vger.kernel.org In-Reply-To: <20261002091029.2225203-3-stefan.roese@mailbox.org> References: <20261002091029.2225203-1-stefan.roese@mailbox.org> <20261002091029.2225203-3-stefan.roese@mailbox.org> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Fri, 02 Oct 2026 09:18:55 +0000 Message-Id: <20261002091856.55CD51F00898@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > pci_configure_rcb() read-modify-writes Link Control of every endpoint > at enumeration, also when RCB is clear in the Root Port and there is > nothing to set. Not writing a register that has nothing to change is > justified on its own, but the write-back of the other Link Control bits > also has side effects on some devices: the Renesas uPD720201 xHCI > (1912:0014) comes out of reset with ASPM L0s and L1 enabled and stops > clearing them itself once Link Control has been written. On a link > whose Root Port supports no ASPM, the previous patch clears them, but > it does not run with pcie_aspm=3Doff or CONFIG_PCIEASPM=3Dn. There the > first access to the xHCI BAR runs into completion timeouts that hang > the system. >=20 > RCB may only be set in an endpoint if it is set in the Root Port, so > there is no need to ever clear it here; an endpoint with RCB set > below a Root Port without it is a firmware configuration error. Only > set RCB, and only when the Root Port has it set. >=20 > Fixes: 1a6845aaa6de ("PCI: Initialize RCB from pci_configure_device()") > Cc: stable@vger.kernel.org > Suggested-by: Bjorn Helgaas > Assisted-by: Claude:claude-opus-5-5 > Signed-off-by: Stefan Roese Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261002091029.2225= 203-1-stefan.roese@mailbox.org?part=3D2