From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wi0-f171.google.com ([209.85.212.171]:32912 "EHLO mail-wi0-f171.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752623AbbJMP0i (ORCPT ); Tue, 13 Oct 2015 11:26:38 -0400 Received: by wicge5 with SMTP id ge5so63274698wic.0 for ; Tue, 13 Oct 2015 08:26:37 -0700 (PDT) Date: Tue, 13 Oct 2015 17:29:04 +0200 From: Daniel Vetter To: Tvrtko Ursulin Cc: Chris Wilson , intel-gfx@lists.freedesktop.org, Daniel Vetter , stable@vger.kernel.org, Jani Nikula Subject: Re: [Intel-gfx] [PATCH] drm/i915: Deny wrapping an userptr into a framebuffer Message-ID: <20151013152904.GJ26718@phenom.ffwll.local> References: <1444742546-27401-1-git-send-email-chris@chris-wilson.co.uk> <561D0E72.9060507@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <561D0E72.9060507@linux.intel.com> Sender: stable-owner@vger.kernel.org List-ID: On Tue, Oct 13, 2015 at 03:00:18PM +0100, Tvrtko Ursulin wrote: > > On 13/10/15 14:22, Chris Wilson wrote: > >Pinning a userptr onto the hardware raises interesting questions about > >the lifetime of such a surface as the framebuffer extends that life > >beyond the client's address space. That is the hardware will need to > >keep scanning out from the backing storage even after the client wants > >to remap its address space. As the hardware pins the backing storage, > >the userptr becomes invalid and this raises a WARN when the clients > >tries to unmap its address space. The situation can be even more > >complicated when the buffer is passed between processes, between a > >client and display server, where the lifetime and hardware access is > >even more confusing. Deny it. > > Reviewed-by: Tvrtko Ursulin Reviewed-by: Daniel Vetter -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch