Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757705Ab1EaUDM (ORCPT ); Tue, 31 May 2011 16:03:12 -0400 Received: from smtp-out.google.com ([216.239.44.51]:40269 "EHLO smtp-out.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752503Ab1EaUDK (ORCPT ); Tue, 31 May 2011 16:03:10 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=google.com; s=beta; h=date:from:x-x-sender:to:cc:subject:in-reply-to:message-id :references:user-agent:mime-version:content-type; b=opRTllvN/lWQYWeYWQ/ds+y+Y7Pmyes6r3MRhlm9eqWbRMNGmunPh39ySUDzoc4NQr 7UbPLYXaRyQupLtcfLyQ== Date: Tue, 31 May 2011 13:03:03 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Russell King - ARM Linux cc: Dmitry Eremin-Solenikov , Nicolas Pitre , linux-arm-kernel , linux-kernel , Eric Miao , Samuel Ortiz Subject: Re: IrDA driver fails on PXA255 In-Reply-To: <20110531072650.GC21382@n2100.arm.linux.org.uk> Message-ID: References: <20110528205701.GA1788@doriath.ww600.siemens.net> <20110529215656.GA5576@n2100.arm.linux.org.uk> <20110531072650.GC21382@n2100.arm.linux.org.uk> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-System-Of-Record: true Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1559 Lines: 33 On Tue, 31 May 2011, Russell King - ARM Linux wrote: > Enabling CONFIG_ZONE_DMA is not a fix, it's making the problem vanish off > the radar. It will mean that the drivers using GFP_DMA will never get > fixed up. > Disabling CONFIG_ZONE_DMA is an optimization, do you agree? I asked on Sunday what the downsides of enabling the option on arm are, and you didn't mention any. So what's the problem with my patch to enable it for this driver since it is using GFP_DMA? You claim that it'll never get removed again to return to the _optimized_ case, yet my patch is guaranteed to work for that driver in all configurations at the moment. I don't think we should be fighting for the optimized case where the alternative has no downside. [ Patching the page allocator to also emit a line to the dmesg to direct users directly to enabling CONFIG_ZONE_DMA wouldn't be a problem, either. ] > Change it to be a soft WARN_ON for one release. Anything else will just > result in the problem being IGNORED. > The problem certainly isn't being ignored in this thread, or in the patch that I sent to fix Dmitry's issue by default, so that doesn't seem to be the case. What would be ignored, though, is if it just emitted a WARN_ON() without failing the allocation so everything works perfectly. -- 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/