From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B9FA8C36002 for ; Mon, 24 Mar 2025 08:20:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=5PvDcdCbkdA1snRxUOF/VjTLlaTTZe/pCAm4cnRw7Io=; b=sluOAWt3DzRlYB3fEfZxHLb9Pq tbAAXfnQrQYn6ivUADbgcyC/6gzSCpT9duEOP15KvZZIAo9kV1bixVraa/EGi0v0RAfxiFd+k92D1 ob7qXS/0cE+2E3bS1xP/Pi/GCbYbZqHs3cJqxOVCoh4fdM+IpeAJ1ln9lMQvi84hOV7mTArlXWJbN CZuleBY8dr6AdmPlKgGouQ2R398i8V34bT19Tl2DqQ7ENPUD/d4qdpZnn/Z3Xw3Xk4zW0L8FZiFtl 8KxNNJgCdBkXS3IDZlydq8SJI76W/O3wqxwYerhJDnkZ4J+9n2gpxvcBBBkT/yNLLtC0vSpHe0Cei aOBQ4cQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.98 #2 (Red Hat Linux)) id 1twd39-00000002Z9X-1cuJ for ath12k@archiver.kernel.org; Mon, 24 Mar 2025 08:20:47 +0000 Received: from sea.source.kernel.org ([172.234.252.31]) by bombadil.infradead.org with esmtps (Exim 4.98 #2 (Red Hat Linux)) id 1twd36-00000002Z8P-2mi2 for ath12k@lists.infradead.org; Mon, 24 Mar 2025 08:20:45 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sea.source.kernel.org (Postfix) with ESMTP id 1C80D437F8; Mon, 24 Mar 2025 08:20:44 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 40E15C4CEDD; Mon, 24 Mar 2025 08:20:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1742804444; bh=pm3PhOm0TA6k02DhynwGtFtiCtph6tpxrXu52vqfi+A=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=TtkgwTkKTiHLTh6W7fKEvie4BMwHRQXCkZE3PdAAoF8K+ndo7kZIa2P/H5Oj4PU0p I2l8EH+wGqKtMjyxfWHlkmX/GLAjqcaUphpl2qnfSCBKbtR5QAcXDXS0/16cl4X3ny o22H7PXPfkDyXMgV/QDLqoXZLy6ckqmEMZcbZ3DtirAwyC4mNDZlTeaI3EMpXOsBOX 0ogQorMDKq3Eu9o+3nh0vohZm7d1qOj/x4Ndg6hcmcTlhsD5aPG0SZFdgJtDpCBUOd D17mDo/elBEMRVVAsR03/EqaPjXfibe9w9wwTbHjwHIv62lZ8d4LTdr9l4oeNAznBg 2IavUGQQ/zySg== Received: from johan by xi.lan with local (Exim 4.97.1) (envelope-from ) id 1twd35-000000004Mc-2Evl; Mon, 24 Mar 2025 09:20:43 +0100 Date: Mon, 24 Mar 2025 09:20:43 +0100 From: Johan Hovold To: Baochen Qiang Cc: Johan Hovold , Jeff Johnson , Stephan Gerhold , ath12k@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] wifi: ath12k: extend dma mask to 36 bits Message-ID: References: <20250321162331.19507-1-johan+linaro@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20250324_012044_720628_626EF92E X-CRM114-Status: GOOD ( 15.02 ) X-BeenThere: ath12k@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "ath12k" Errors-To: ath12k-bounces+ath12k=archiver.kernel.org@lists.infradead.org On Mon, Mar 24, 2025 at 04:05:33PM +0800, Baochen Qiang wrote: > On 3/24/2025 3:40 PM, Johan Hovold wrote: > > On Mon, Mar 24, 2025 at 11:06:16AM +0800, Baochen Qiang wrote: > >> On 3/22/2025 12:23 AM, Johan Hovold wrote: > >>> Extend the DMA mask to 36 bits to avoid using bounce buffers on machines > >>> without an iommu (under OS control) similar to what was done for ath11k > >>> in commit dbd73acb22d8 ("wifi: ath11k: enable 36 bit mask for stream > >>> DMA"). > >>> > >>> This specifically avoids using bounce buffers on Qualcomm Snapdragon X > >>> Elite machines like the Lenovo ThinkPad T14s when running at EL1. > >>> Note that the mask could possibly be extended further but unresolved DMA > >>> issues with 64 GiB X Elite machines currently prevents that from being > >>> tested. > >> > >> could you help elaborate how it could be extended? > > > > The mask should reflect the capability of the device. That may be > > 64 (or 40) bits, but I've only been able to test using 36 bits. > > are you talking about QCN9274? As far as I know, WCN7850 does not support 40 bits or more. Or really all devices handled by ath12k since they at least currently use a common mask. The T14s has a: 0004:01:00.0 Network controller: Qualcomm Technologies, Inc WCN785x Wi-Fi 7(802.11be) 320MHz 2x2 [FastConnect 7800] (rev 01) ath12k_pci 0004:01:00.0: Hardware name: wcn7850 hw2.0 ath12k_pci 0004:01:00.0: chip_id 0x2 chip_family 0x4 board_id 0xff soc_id 0x40170200 Sounds like 36 bits is the correct choice for now then. Johan