From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [PATCH] drm/i915: Support 64b relocations Date: Mon, 5 May 2014 16:06:21 +0200 Message-ID: <20140505140621.GL20800@phenom.ffwll.local> References: <1398730708-3278-1-git-send-email-benjamin.widawsky@intel.com> <20140501080450.GF3438@nuc-i3427.alporthouse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail-ee0-f53.google.com (mail-ee0-f53.google.com [74.125.83.53]) by gabe.freedesktop.org (Postfix) with ESMTP id 9AAA36E8EA for ; Mon, 5 May 2014 07:06:26 -0700 (PDT) Received: by mail-ee0-f53.google.com with SMTP id b15so4277121eek.26 for ; Mon, 05 May 2014 07:06:25 -0700 (PDT) Content-Disposition: inline In-Reply-To: <20140501080450.GF3438@nuc-i3427.alporthouse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: intel-gfx-bounces@lists.freedesktop.org Sender: "Intel-gfx" To: Chris Wilson , Ben Widawsky , Intel GFX , Rafael Barbalho List-Id: intel-gfx@lists.freedesktop.org On Thu, May 01, 2014 at 09:04:50AM +0100, Chris Wilson wrote: > On Mon, Apr 28, 2014 at 05:18:28PM -0700, Ben Widawsky wrote: > > All the rest of the code to enable this is in my branch. Without my > > branch, hitting > 32b offsets is impossible. The code has always > > "supported" 64b, but it's never actually been run of tested. This change > > doesn't actually fix anything. [1] I am not sure why X won't work yet. I > > do not get hangs or obvious errors. > > > > There are 3 fixes grouped together here. First is to remove the > > hardcoded 0 for the upper dword of the relocation. The next fix is to > > use a 64b value for target_offset. The final fix is to not directly > > apply target_offset to reloc->delta. reloc->delta is part of ABI, and so > > we cannot change it. As it stands, 32b is enough to represent everything > > we're interested in representing anyway. The main problem is, we cannot > > add greater than 32b values to it directly. Imo if you have a target_offset > 32b in a valid use-case we can bother to look at this. But not before, since I expect that hw advances will make this obsolete anyway. > > [1] Almost all of intel-gpu-tools is not yet ready to test 64b > > relocations. There are a few places that expect 32b values for offsets > > and these all won't work. > > > > Cc: Rafael Barbalho > > Cc: Chris Wilson > > Signed-off-by: Ben Widawsky > > Seriously, we did this? I am ashamed. I was annoyed by the original > assertion that no userspace was ready in the first place, and to see > that the code was a complete farce anyway... Well my idea was that we try to prep userspace to avoid a needless abi rev, but it was always clear to me that the kernel side (and igt) is hopelessly broken for 64b relocs. > Reviewed-by: Chris Wilson Queued for -next, thanks for the patch. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation +41 (0) 79 365 57 48 - http://blog.ffwll.ch