From mboxrd@z Thu Jan 1 00:00:00 1970 From: brian.starkey@arm.com (Brian Starkey) Date: Fri, 10 Mar 2017 10:31:13 +0000 Subject: [RFC PATCH 00/12] Ion cleanup in preparation for moving out of staging In-Reply-To: <26bc57ae-d88f-4ea0-d666-2c1a02bf866f@redhat.com> References: <1488491084-17252-1-git-send-email-labbott@redhat.com> <20170303132949.GC31582@dhcp22.suse.cz> <20170306074258.GA27953@dhcp22.suse.cz> <20170306104041.zghsicrnadoap7lp@phenom.ffwll.local> <20170306105805.jsq44kfxhsvazkm6@sirena.org.uk> <20170306160437.sf7bksorlnw7u372@phenom.ffwll.local> <26bc57ae-d88f-4ea0-d666-2c1a02bf866f@redhat.com> Message-ID: <20170310103112.GA15945@e106950-lin.cambridge.arm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Hi, On Thu, Mar 09, 2017 at 09:38:49AM -0800, Laura Abbott wrote: >On 03/09/2017 02:00 AM, Benjamin Gaignard wrote: [snip] >> >> For me those patches are going in the right direction. >> >> I still have few questions: >> - since alignment management has been remove from ion-core, should it >> be also removed from ioctl structure ? > >Yes, I think I'm going to go with the suggestion to fixup the ABI >so we don't need the compat layer and as part of that I'm also >dropping the align argument. > Is the only motivation for removing the alignment parameter that no-one got around to using it for something useful yet? The original comment was true - different devices do have different alignment requirements. Better alignment can help SMMUs use larger blocks when mapping, reducing TLB pressure and the chance of a page table walk causing display underruns. -Brian