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 1683532D7F8; Sat, 12 Sep 2026 18:16:05 +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=1789236967; cv=none; b=HuluXllilPDaLAJzEQtOYuH0aeB6ESxw6XtaaxIaA7dcYX0U0oe2TNJy6NHjYt5tEDqkipYwN0uIBEDXNijTSYffq+cMZjFL7iG+nSYWoeJP+NwsNYpEZv8hVKT1N1YiXSZa0dPrT9ttZdNQYnqCBV38hORTg7E+I1M0MSCjnaM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789236967; c=relaxed/simple; bh=iYlV5wTAjMs3k1tGiE0VqPJcKu8biY4XIG5dRVUIj/4=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=FpW0fqedWbiVHN9bbkyA3I0G2zOfFMR9S33YNmjAapeqtFJsntCYRYzNVNTrCjGn1iQMFiPqqaxxxKOC1t5rT5RFzPd+YnUQJHTLlgpeRMa5AyLd84OmpeqYq4wNVoT4tGVVeDyH4MkiS5/qvjQaU1oF1tvNfNCITteOmK4vFE8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=1Jnfubdm; 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="1Jnfubdm" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CAC9F1F000FF; Sat, 12 Sep 2026 18:16:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789236965; bh=cwYbxW8EdvDA013BVlQSroIkhc2cmFF0ye7sMVJumkw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1JnfubdmD2Yeg0/qfK7tZuk/9JuANpyCokMG7I87KPIlPtqTOt10b9XP2vSJflHp9 1qvulGTk5huPKfLXwqEPkZt0+20DqFoT18ZlXdW3GH15QPXoh+dICaW/NA+4aUeMhT rV6b7XNIwvJw0yNAMmyYfZumM3UOgwGlf4FuQWwM= 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 5.15 161/935] PCI: Fix 32-bit config write in Intel PCH Root Port MPC ACS quirk Date: Sat, 12 Sep 2026 08:53:11 +0200 Message-ID: <20260912065530.513897485@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065526.833703348@linuxfoundation.org> References: <20260912065526.833703348@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 5.15-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 @@ -5195,7 +5195,7 @@ 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); } }