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 8650937CD3E; Sat, 12 Sep 2026 19:31:19 +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=1789241482; cv=none; b=k9tN5kJ/vPQpMVtwrP7YowP8pc1SjN20ARdM3G4ZUFSBA6ZL9br1RrLMsCt/+LBrmkH8kuNHWCLriiAu5HdiT1DK6xzuiMyvdzWoQoqhYzkegSbeynBEKbMkbn1eNyYoJ/XvAqFRqrBwDDq0vTaPQhemgA76tKPJRHlIPxM6iTk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789241482; c=relaxed/simple; bh=KzQVptm0F7VEXztl27NLmecyrfSP/udWDPCcg2cuwpc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GT1SGW3ja0C4A07zruDMbEadb+40XmsdVDmlvd97xQo6jjPaSFnlItd9Z8Um/QD3MXfIq55Q1ZnQJigbyV19+olfzuaQNW/UbpKJYA5HNstbvsrO3+jgiooEaMBnfVaGO9TYVsuPq3LRFCKdzrNLpRI2+EAXoAXn/wV336OBp+c= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=guiAwZ8F; 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="guiAwZ8F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5625A1F000FF; Sat, 12 Sep 2026 19:31:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789241478; bh=dYV7VYa6LQaZ5RGkQv1u2Mq+G8VXSNvETMEzt56BmUY=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=guiAwZ8F6vwILYJQz1GwsuedqQEYg9k4l8gqZTIlYOt0bpkFP9574vZG1bAuomJ7J iKx5fQNoQdmW53OHqgoz+EaK5M2MM/tePYrVckg6+R1aejz+OwCzMMcViFRMgfDSFc DBQ/wN8Wvzy4g8IKpZ2FJLvkbV3xnkl+Ll6OEnfE= 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 5.10 142/798] PCI: Fix 32-bit config write in Intel PCH Root Port MPC ACS quirk Date: Sat, 12 Sep 2026 08:56:10 +0200 Message-ID: <20260912065520.236271825@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065516.948645775@linuxfoundation.org> References: <20260912065516.948645775@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 5.10-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 @@ -5169,7 +5169,7 @@ 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); } }