From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755167Ab1KNLmW (ORCPT ); Mon, 14 Nov 2011 06:42:22 -0500 Received: from ch1ehsobe006.messaging.microsoft.com ([216.32.181.186]:36164 "EHLO ch1outboundpool.messaging.microsoft.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752091Ab1KNLmV (ORCPT ); Mon, 14 Nov 2011 06:42:21 -0500 X-SpamScore: -18 X-BigFish: VPS-18(zz1432N98dKzz1202hzz15d4Rz32i668h839h944h) X-Forefront-Antispam-Report: CIP:163.181.249.108;KIP:(null);UIP:(null);IPVD:NLI;H:ausb3twp01.amd.com;RD:none;EFVD:NLI X-FB-SS: 0, X-WSS-ID: 0LUNF6G-01-2DW-02 X-M-MSG: Date: Mon, 14 Nov 2011 12:42:13 +0100 From: Joerg Roedel To: Larry Finger CC: LKML , , USB list Subject: Re: nommu warning message Message-ID: <20111114114213.GC14704@amd.com> References: <4EBD65F5.8090808@lwfinger.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <4EBD65F5.8090808@lwfinger.net> User-Agent: Mutt/1.5.21 (2010-09-15) X-OriginatorOrg: amd.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 11, 2011 at 12:14:13PM -0600, Larry Finger wrote: > For the driver rtl8192cu (a USB wireless device), the current > version loads the 15KB firmware asynchronously one 32-bit quantity > at a time. Although inefficient. this method works with USB 1.1 and > USB 2.0 adapters; however, it fails on at least one USB 3.0 adapter > with "xhci_hcd 0000:05:00.0: ERROR no room on ep ring" errors. > > These errors are believed to arise from small, fixed-size ep rings. > There is a vendor driver that works with that same hardware. The > major difference is that it uses synchronous block writes of 254 > bytes. When I tried this with the in-kernel driver, each block write > yields a warning as shown below: > > nommu_map_single: overflow 41000340d020+254 of device mask ffffffff Strange. This means that your system uses the nommu DMA driver. But for your hardware the GART or SWIOTLB should be used. Even more strange is the address used for the device. I don't believe is is correct, otherwise your Laptop would have a very huge amount of RAM :) The I think there are two issues here: Why is your system using nommu and not GART? Can you check that GART and SWIOTLB are enabled in your kernel config? Second, why is your system using the wrong address? This looks like some kind of driver bug to mee. Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632