From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161166AbcFGOv6 (ORCPT ); Tue, 7 Jun 2016 10:51:58 -0400 Received: from foss.arm.com ([217.140.101.70]:45379 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755611AbcFGOv4 (ORCPT ); Tue, 7 Jun 2016 10:51:56 -0400 Date: Tue, 7 Jun 2016 15:51:53 +0100 From: liviu.dudau@arm.com To: Robin Murphy , airlied@linux.ie, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] drm/fb_cma_helper: Implement fb_mmap callback Message-ID: <20160607145153.GF1165@e106497-lin.cambridge.arm.com> References: <8fd95ac1440e0f01daad6d4380be3a4c8fa61055.1465301219.git.robin.murphy@arm.com> <20160607144305.GC3363@phenom.ffwll.local> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20160607144305.GC3363@phenom.ffwll.local> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jun 07, 2016 at 04:43:05PM +0200, Daniel Vetter wrote: > On Tue, Jun 07, 2016 at 01:18:09PM +0100, Robin Murphy wrote: > > In the absence of an fb_mmap callback, the fbdev code falls back to a > > naive implementation which relies upon the DMA address being the same > > as the physical address, and the buffer being physically contiguous > > from there. Whilst this often holds for standard CMA allocations via > > the platform's regular DMA ops, if the allocation is provided by an > > IOMMU then such assumptions can fall apart spectacularly. > > > > To resolve this, reroute the fb_mmap call to the appropriate DMA API > > implementation, as per the other cma_helper calls. > > > > Acked-by: Daniel Vetter > > Signed-off-by: Robin Murphy > > --- > > > > Resending rebased to 4.7-rc1 with Daniel's ack. I know Russell raised > > some concerns about the general way fb_cma_helper uses fb_info[1], but > > AFAICS that's a longstanding separate problem orthogonal to this patch. > > Do you want me to pull this in through drm-misc, or will this land through > some driver tree? Note that I'll do -misc pulls about every week, so if > you don't send your pull this week I'd like to pull it in to avoid > hilarity^W needless conflicts. > -Daniel Hi Daniel, This patch is for drm core, so no driver can carry it (?). Please pull it into your drm-misc. Best regards, Liviu > > > > > Robin. > > > > [1]:http://thread.gmane.org/gmane.comp.video.dri.devel/149288 > > > > drivers/gpu/drm/drm_fb_cma_helper.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_fb_cma_helper.c b/drivers/gpu/drm/drm_fb_cma_helper.c > > index 172cafe11c71..a25afc068d3f 100644 > > --- a/drivers/gpu/drm/drm_fb_cma_helper.c > > +++ b/drivers/gpu/drm/drm_fb_cma_helper.c > > @@ -23,6 +23,7 @@ > > #include > > #include > > #include > > +#include > > #include > > > > #define DEFAULT_FBDEFIO_DELAY_MS 50 > > @@ -297,6 +298,12 @@ int drm_fb_cma_debugfs_show(struct seq_file *m, void *arg) > > EXPORT_SYMBOL_GPL(drm_fb_cma_debugfs_show); > > #endif > > > > +static int drm_fb_cma_mmap(struct fb_info *info, struct vm_area_struct *vma) > > +{ > > + return dma_mmap_writecombine(info->device, vma, info->screen_base, > > + info->fix.smem_start, info->fix.smem_len); > > +} > > + > > static struct fb_ops drm_fbdev_cma_ops = { > > .owner = THIS_MODULE, > > .fb_fillrect = drm_fb_helper_sys_fillrect, > > @@ -307,6 +314,7 @@ static struct fb_ops drm_fbdev_cma_ops = { > > .fb_blank = drm_fb_helper_blank, > > .fb_pan_display = drm_fb_helper_pan_display, > > .fb_setcmap = drm_fb_helper_setcmap, > > + .fb_mmap = drm_fb_cma_mmap, > > }; > > > > static int drm_fbdev_cma_deferred_io_mmap(struct fb_info *info, > > -- > > 2.8.1.dirty > > > > -- > Daniel Vetter > Software Engineer, Intel Corporation > http://blog.ffwll.ch > -- ==================== | I would like to | | fix the world, | | but they're not | | giving me the | \ source code! / --------------- ¯\_(ツ)_/¯