Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755629Ab1E2V5T (ORCPT ); Sun, 29 May 2011 17:57:19 -0400 Received: from caramon.arm.linux.org.uk ([78.32.30.218]:41873 "EHLO caramon.arm.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752799Ab1E2V5S (ORCPT ); Sun, 29 May 2011 17:57:18 -0400 Date: Sun, 29 May 2011 22:56:56 +0100 From: Russell King - ARM Linux To: David Rientjes Cc: Dmitry Eremin-Solenikov , Nicolas Pitre , linux-arm-kernel , linux-kernel , Eric Miao , Samuel Ortiz Subject: Re: IrDA driver fails on PXA255 Message-ID: <20110529215656.GA5576@n2100.arm.linux.org.uk> References: <20110528205701.GA1788@doriath.ww600.siemens.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.19 (2009-01-05) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1316 Lines: 29 On Sun, May 29, 2011 at 02:17:02PM -0700, David Rientjes wrote: > On Sun, 29 May 2011, Dmitry Eremin-Solenikov wrote: > > > What about changing your patch for less intrusive one (to emit a > > WARN_ON) for at least one > > or two major releases and only then changing it back to the current state? > > > > That would return memory that is not guaranteed to be within the first > 16MB of address space, so a GFP_DMA allocation would succeed with memory > not from ZONE_DMA. Err, no. GFP_DMA returns memory in a zone which the platform has setup. There's nothing specific about it being "16MB" or any other size; the arch can chose what size that is. > That's an invalid configuration, so users, including > you, should at least edit their .config by hand to enable CONFIG_ZONE_DMA > as a workaround. Again, no. This change has caused a load of previously working drivers to suddenly start failing without _any_ explanation why or even warning about the change. It needs to start off as a WARN_ON() so that stuff can be fixed, and then changed to a hard error. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/