From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gw-1.arm.linux.org.uk ([78.32.30.217]:32829 "EHLO pandora.arm.linux.org.uk" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756353AbaCTP04 (ORCPT ); Thu, 20 Mar 2014 11:26:56 -0400 Date: Thu, 20 Mar 2014 15:26:40 +0000 From: Russell King - ARM Linux To: Ben Dooks Cc: Arnd Bergmann , linux-sh@vger.kernel.org, "linux-pci@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Magnus Damm , Ben Dooks , Bjorn Helgaas , Simon Horman , linux-arm-kernel@lists.infradead.org Subject: Re: DMABOUNCE in pci-rcar Message-ID: <20140320152640.GW7528@n2100.arm.linux.org.uk> References: <201402241200.21944.arnd@arndb.de> <5165962.7bqj51B15Z@wuerfel> <532B0384.1000400@codethink.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <532B0384.1000400@codethink.co.uk> Sender: linux-pci-owner@vger.kernel.org List-ID: On Thu, Mar 20, 2014 at 04:04:36PM +0100, Ben Dooks wrote: > On 26/02/14 20:57, Arnd Bergmann wrote: >> On Wednesday 26 February 2014 12:48:17 Bjorn Helgaas wrote: >>> On Mon, Feb 24, 2014 at 4:00 AM, Arnd Bergmann wrote: >>>> Hi Magnus, >>>> >>>> I noticed during randconfig testing that you enabled DMABOUNCE for the >>>> pci-rcar-gen2 driver as posted in this patch https://lkml.org/lkml/2014/2/5/30 >>>> >>>> I didn't see the original post unfortunately, but I fear we have to >>>> revert it and come up with a better solution, ... >>> >>> Sounds like I should drop the following patches from my pci/host-rcar >>> branch for now? >>> >>> PCI: rcar: Add DMABOUNCE support >>> PCI: rcar: Enable BOUNCE in case of HIGHMEM >>> PCI: rcar: Make the Kconfig dependencies more generic >> >> Sounds good to me. The last patch is actually fine, but you'll have to >> fix the context to apply it without the other two. > > As a note, if we now boot a Lager with DT on 3.14-rc3 series the USB > controllers no longer work with full 2GiB RAM enabled in the device > tree. > > Could we work around this by having 1GiB of memory defined in the > 32bit memory and then add the rest of the 3GiB from the >32bit > area via LPAE? Will the kernel ever try to allocate DMA memory from > anything >32bit? Ignore highmem. What is the actual hardware restriction concerning memory it can access? -- FTTC broadband for 0.8mile line: now at 9.7Mbps down 460kbps up... slowly improving, and getting towards what was expected from it.