From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bmailout3.hostsharing.net (bmailout3.hostsharing.net [176.9.242.62]) (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 82D616995B; Tue, 12 Mar 2024 07:50:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=176.9.242.62 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710229816; cv=none; b=sm8Np5TJnwFIVPGIpk0mNNgna9jk44jRPzuHJi9ZYGoukLs4MvFjjFNpXxGJGrHl+A5XthpxPqqYJMfq8Tvjtfrf9bvQ7VyaNBKx4rgC9bv2/2l6222CN7GiEBcaxTXChBNrkZYjz7PbIyaHiJ0F6MeXRyKHSNolh6xq5Gm+zHs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1710229816; c=relaxed/simple; bh=h6DM/hM1xlKy3Hc7CpFU3ajXUunOj0LnS5nJ9tulN8E=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=YqJqZ156dLXGhlCgoE/SGfaDow6HRjfClaT8saaaFOWqS62S9JXMhSuuHSpTg1bCT0o5722HCHDZIys46Mv5feo13c6RH9FyWnbnceM6NDK1uGTu+L5UKQ7/CW4NZrjxGDrDNAnDRA4XJpJfQFZ4RkP3bO1GlhZLvmi0ewNOjyA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de; spf=none smtp.mailfrom=h08.hostsharing.net; arc=none smtp.client-ip=176.9.242.62 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=wunner.de Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=h08.hostsharing.net Received: from h08.hostsharing.net (h08.hostsharing.net [83.223.95.28]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256 client-signature RSA-PSS (4096 bits) client-digest SHA256) (Client CN "*.hostsharing.net", Issuer "RapidSSL TLS RSA CA G1" (verified OK)) by bmailout3.hostsharing.net (Postfix) with ESMTPS id 5A642100DA1C9; Tue, 12 Mar 2024 08:50:10 +0100 (CET) Received: by h08.hostsharing.net (Postfix, from userid 100393) id 3BA1423A014; Tue, 12 Mar 2024 08:50:10 +0100 (CET) Date: Tue, 12 Mar 2024 08:50:10 +0100 From: Lukas Wunner To: Dave Jiang Cc: linux-cxl@vger.kernel.org, linux-pci@vger.kernel.org, dan.j.williams@intel.com, ira.weiny@intel.com, vishal.l.verma@intel.com, alison.schofield@intel.com, Jonathan.Cameron@huawei.com, dave@stgolabs.net, bhelgaas@google.com Subject: Re: [PATCH 2/3] PCI: Create new reset method to force SBR for CXL Message-ID: References: <20240311204132.62757-1-dave.jiang@intel.com> <20240311204132.62757-3-dave.jiang@intel.com> Precedence: bulk X-Mailing-List: linux-pci@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240311204132.62757-3-dave.jiang@intel.com> On Mon, Mar 11, 2024 at 01:39:54PM -0700, Dave Jiang wrote: > CXL spec r3.1 8.1.5.2 > By default Secondary Bus Reset (SBR) is masked for CXL ports. Introduce a > new PCI reset method "cxl_bus_force" to force SBR on CXL ports by setting > the unmask SBR bit in the CXL DVSEC port control register before performing > the bus reset and restore the original value of the bit post reset. Hm, why not have a sysfs attribute (or sysctl variable) to unmask SBR? That would avoid the need to touch pci code as the sysfs attribute could be kept local to the cxl subsystem. Thanks, Lukas