On Tue, Jun 07, 2016 at 04:03:40PM +0100, Robin Murphy wrote: > On 07/06/16 15:43, 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 <daniel.vetter at ffwll.ch> > > > Signed-off-by: Robin Murphy <robin.murphy at arm.com> > > > --- > > > > > > 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. > > Yeah, drm-misc sounds appropriate so if you're happy to pick it up, please > feel free :)
Applied, thanks. -Daniel > > Robin. > > > -Daniel > > > > > > > > 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 <drm/drm_crtc_helper.h> > > > #include <drm/drm_gem_cma_helper.h> > > > #include <drm/drm_fb_cma_helper.h> > > > +#include <linux/dma-mapping.h> > > > #include <linux/module.h> > > > > > > #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 > > > > > > > _______________________________________________ > dri-devel mailing list > dri-devel at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
