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 EBD6AC5DF7E for ; Tue, 18 Aug 2026 15:29:38 +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:Content-Transfer-Encoding: Content-Type:MIME-Version:References:In-Reply-To:Message-ID:Subject:Cc:To: From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=Fu2n3BnOxXot3kZ7+JaRDlx1+WuO9eZ8yLgzOEaQxiY=; b=zKpFFfJvVp4VKLQsfse8cnMX1Z 0QEB/86Jkm/pWggT5HSgFn/bICSsg2m9uQsTFvrnazMi4eXQY5HWSkDhtuFlnetSNE6Yqik+6j0TJ L4e0+pbCtkPReYeT1WmteFKVEMsOXubaOcKLNM4WxokiIdxW/LrbfuNWsuRCziKIfj44TToTKAzEv MQv5t1gbYUVML0seXL7p7VyPdtE97AQd6ODfidBhqykYRrRKJ7xcj2sImOMgv4NbISJtBzohxp0Sn 0zQX9WFq4OMCwZvXFSbIMhjX8ggkrg39J2e67RjBK0svHqXKd12fWeOX0F67jFQkcZOOSsarqNX7S Nc28V2wg==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwLkv-00000008GZe-3CEo; Tue, 18 Aug 2026 15:29:37 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wwLkt-00000008GYj-3101; Tue, 18 Aug 2026 15:29:35 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 0BD274077F; Tue, 18 Aug 2026 15:29:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id A09141F000E9; Tue, 18 Aug 2026 15:29:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1787066974; bh=Fu2n3BnOxXot3kZ7+JaRDlx1+WuO9eZ8yLgzOEaQxiY=; h=Date:From:To:Cc:Subject:In-Reply-To:References; b=M7fhLpkcm85yYr+S4YvfDk1ZyJ0JikJVkvVqSs5a7i77lp3GCICaHjW1TJIyAQ5ky 8w+v+8WEzKxNtwatOg9DdmOrIElZNO5Zlbmizi2D4OORnK5fg10I2vHWkke1+VMzPq QJ9C7QAWGWu/U8WRFC4tyy/fxWoObOX0U/pgGPqesbVP9dGPbY3EPK8KB5ZR2jRrs6 wGWdlUDa/krBtcqSBTt2kj61cXxJavNI359zUk4zs+zLYlY3kIUvU46z4IgoksZokc PKcrVKXMIf4bULIjHuEVp4wam/bI0Mprh7JoMf3qzXAFUNJaqEoPypnX6ZpBHxNhEy qhZYgee67Esuw== Date: Tue, 18 Aug 2026 08:29:33 -0700 From: Jakub Kicinski To: Daniel Pawlik Cc: netdev@vger.kernel.org, lorenzo@kernel.org, win847@gmail.com, linux-arm-kernel@lists.infradead.org, linux-mediatek@lists.infradead.org Subject: Re: [PATCH v8] net: airoha: npu: use cacheline-sized buffers for mailbox DMA Message-ID: <20260818082933.28b5c9d1@kernel.org> In-Reply-To: References: <20260817090601.1256389-1-pawlik.dan@gmail.com> <20260817161756.5fd2185a@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Tue, 18 Aug 2026 08:23:33 +0200 Daniel Pawlik wrote: > v8 does not switch to coherent DMA; it only rounds up mailbox payload > allocations (dma_get_cache_alignment() in v9) and maps the same rounded > length with DMA_BIDIRECTIONAL, while the mailbox length register still > uses the original payload size. On this board, mapping only the payload > size regresses probe back to 0.0 even with the larger allocation, so the > rounded map length seems required here. Please trace into the dma API implementation on this platform where the alignment makes a difference. The "unaligned length" path must be buggy. We should fix it there, not in all the drivers (my concern being that this is not the only driver that hits the issue).