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 78A903E866B; Fri, 4 Sep 2026 05:56:19 +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=1788501380; cv=none; b=ljTYhyC0hjdM+2cQZ12aqDel3rz8VTb/joYOnMfp+UBqJId3aE8+9pbhku8bpElXqnT2V7ykDlc9PmnLivLEkY2TvVsd5VP1VH3cfU2z64qJt1j/9Vk2OlQsMuEp2FJLavoQVZGefg90qhAvabjOzgO86jjBC9ToCKaTbJldcII= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501380; c=relaxed/simple; bh=5h4WZZFort5AA9liGcMQAIKLYqoMPWCZLXh60CzPOlk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=YBPwW8f1vrgQOVG4a5VGRvnWJjrbtzFrkU8B7IYJNf7ZMINXjlvR0VVR89/MXbVWUWn/6P/94oWx2nmbs9ADPrmSefnegPPQD39sZT4W6oTfD74+930POJYYzxo7/tFymT9Wu13xrpxLvEsceHaeIrF1aqn2rKaEH13XZI52s24= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=z1EnVxi3; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="z1EnVxi3" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 677A81F00A3D; Fri, 4 Sep 2026 05:56:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501378; bh=xAVQMmJXF1AfdvYt+wsSp0HGDGR6er7cQDqU08kmhoQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=z1EnVxi3uo+NCdBSChVQl0ZDRY29Sg3NSvKNWSIYFQLpVHabFddm5GLUpEmHnkJVi 87iwN/ZGRkOoDYC5tCitLmIUurBTqy1ND4cZg7sMlQN3Xpn2rix0K8Zx8wa/yT0BCN q0W+HiGk2wL6xagDtizMIuM7h6siJGvmOX47VB7Q= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Mohamad Raizudeen , Bjorn Helgaas , Manivannan Sadhasivam Subject: [PATCH 6.18 387/552] PCI: Fix 32-bit config write in Intel PCH Root Port MPC ACS quirk Date: Fri, 4 Sep 2026 06:59:04 +0200 Message-ID: <20260904045758.982509561@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mohamad Raizudeen commit 23d7eed5974989de56273c964d7e510e4aad91e8 upstream. pci_quirk_enable_intel_rp_mpc_acs() reads a 32-bit DWORD from the MPC register, sets bit 26 (INTEL_MPC_REG_IRBNCE), but it writes it back using pci_write_config_word(). Because bit 26 resides in the upper 16 bits of the 32-bit register, a 16-bit write drops the newly set bit. The quirk logs that it is enabling IRBNCE, but the hardware never actually receives the command. Use pci_write_config_dword() to ensure the full 32-bit value is written back to the hardware. Fixes: d99321b63b1f ("PCI: Enable quirks for PCIe ACS on Intel PCH root ports") Signed-off-by: Mohamad Raizudeen Signed-off-by: Bjorn Helgaas Reviewed-by: Manivannan Sadhasivam Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260723171203.4892-1-raizudeen.kerneldev@gmail.com Signed-off-by: Greg Kroah-Hartman --- drivers/pci/quirks.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/pci/quirks.c +++ b/drivers/pci/quirks.c @@ -5331,7 +5331,7 @@ static void pci_quirk_enable_intel_rp_mp if (!(mpc & INTEL_MPC_REG_IRBNCE)) { pci_info(dev, "Enabling MPC IRBNCE\n"); mpc |= INTEL_MPC_REG_IRBNCE; - pci_write_config_word(dev, INTEL_MPC_REG, mpc); + pci_write_config_dword(dev, INTEL_MPC_REG, mpc); } }