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 B42263B42F7; Fri, 4 Sep 2026 06:17:47 +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=1788502668; cv=none; b=p+7kvcP5UpTcCcHhYpuGN1e2yxan9Ka+d436oGvfwlXaywFXPMy9boyj8jFo/CPHJ16bGvfSA8Iltvd9MQMF2GiFb8kY4XkqGaJuTo6IsOTmepyeuK9RJbuWIZtZR0dpBTI0k0d4RNpHZuD6Y5w2YcD/GBFzA68SKPb49kZPsvg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788502668; c=relaxed/simple; bh=1ooHKTz6ZH6moN34VGNQd/T+qEH+XCV30r22EJGu27U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=E8e7YPe311CE1tUNAe+IBHyaHl0YVK3Rx+8xvmir80+Gi1J7EMg+8bZodXNFw7FrkJIaY84zNqVmMSxGs4blCSQ0ZrQgtjoBLD1wTrGivIefghdEHhjWKHA2wHaGIg1opiZx5WabT9Tic2OF4jdMCTXb0soRI1iO3XB49ETsJMM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=bOojotYw; 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="bOojotYw" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1923A1F00A3D; Fri, 4 Sep 2026 06:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788502667; bh=GGw4uCO8CSn9l8rtuUHiDcq65D+tXGq1rl8tec9z9GU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=bOojotYwkr54MF60StI0Hwquw+pUpt4l9BlL21X3RJmH82UlGvI4hcJ7PgOq4yKP6 LtiQbMB9OGdp2+KenlnJipqJpJbTRPIO9trsgwxC7RcsCGBQY1Z2eFQX3YmgxEBRFk nMssxATnb5ve5SJuTnpFg1C3WMnIcbX2sT1Tzk8U= 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 6.12 289/403] PCI: Fix 32-bit config write in Intel PCH Root Port MPC ACS quirk Date: Fri, 4 Sep 2026 07:01:32 +0200 Message-ID: <20260904045741.422863683@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045734.806166532@linuxfoundation.org> References: <20260904045734.806166532@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-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 @@ -5325,7 +5325,7 @@ 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); } }