From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from na01-bn1-obe.outbound.protection.outlook.com (mail-bn1bon0146.outbound.protection.outlook.com [157.56.111.146]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id B2A8E1A029F for ; Tue, 14 Oct 2014 20:44:47 +1100 (EST) Message-ID: <1413279865.2878.20.camel@aoeu.buserror.net> Subject: Re: [PATCH 1/4] powerpc: Dynamic DMA zone limits From: Scott Wood To: Benjamin Herrenschmidt Date: Tue, 14 Oct 2014 11:44:25 +0200 In-Reply-To: <1413273473.26478.52.camel@pasglop> References: <1407541245-27617-1-git-send-email-scottwood@freescale.com> <20141013181436.300988c8@kryten> <1413190849.21457.4.camel@concordia> <1413272346.2878.2.camel@aoeu.buserror.net> <1413273473.26478.52.camel@pasglop> Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Cc: linuxppc-dev@lists.ozlabs.org, Anton Blanchard , Shaohui Xie List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On Tue, 2014-10-14 at 18:57 +1100, Benjamin Herrenschmidt wrote: > On Tue, 2014-10-14 at 09:39 +0200, Scott Wood wrote: > > For a short-term workaround, I'd rather leave CONFIG_ZONE_DMA32 where > > it > > is and put #ifdef CONFIG_FSL_SOC (with a comment) around the whole > > thing. > > I'd like to not enable CONFIG_ZONE_DMA32 when we don't need it, ie, > on !BOOKE 64-bit How does 64-bit powermac deal with it, with random PCI cards? Does it use an IOMMU for coherent allocations? In any case, CONFIG_ZONE_DMA32 should be harmless if the zone isn't dynamically created, but we can limit it to booke if you want. The current breakage has nothing to do with ZONE_DMA32, but rather to the fact that we now check zones at all. This is why I'd rather have the short term workaround be a new ifdef, rather than moving ifdef CONFIG_ZONE_DMA32 (moving it also obscures the way the code should look if and when the workaround can be removed). -Scott