From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751318AbeDYHas (ORCPT ); Wed, 25 Apr 2018 03:30:48 -0400 Received: from mail-wm0-f46.google.com ([74.125.82.46]:55712 "EHLO mail-wm0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750962AbeDYHan (ORCPT ); Wed, 25 Apr 2018 03:30:43 -0400 X-Google-Smtp-Source: AIpwx48bDAklW7u9ErwO3Yn2Z+A/YrCmRhe+FiNfPcKeWUdKJ2GLAvLkLrvp0mrf2S9mcrz6bTF6Zw== Date: Wed, 25 Apr 2018 09:30:39 +0200 From: Daniel Vetter To: Christoph Hellwig Cc: Daniel Vetter , Christian =?iso-8859-1?Q?K=F6nig?= , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Linux Kernel Mailing List , amd-gfx list , Jerome Glisse , dri-devel , Dan Williams , Logan Gunthorpe , "open list:DMA BUFFER SHARING FRAMEWORK" , Thierry Reding Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag Message-ID: <20180425073039.GO25142@phenom.ffwll.local> Mail-Followup-To: Christoph Hellwig , Christian =?iso-8859-1?Q?K=F6nig?= , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Linux Kernel Mailing List , amd-gfx list , Jerome Glisse , dri-devel , Dan Williams , Logan Gunthorpe , "open list:DMA BUFFER SHARING FRAMEWORK" , Thierry Reding References: <20180420124625.GA31078@infradead.org> <20180420152111.GR31310@phenom.ffwll.local> <20180424184847.GA3247@infradead.org> <20180425054855.GA17038@infradead.org> <20180425064335.GB28100@infradead.org> <20180425070905.GA24827@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180425070905.GA24827@infradead.org> X-Operating-System: Linux phenom 4.15.0-1-amd64 User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 25, 2018 at 12:09:05AM -0700, Christoph Hellwig wrote: > On Wed, Apr 25, 2018 at 09:02:17AM +0200, Daniel Vetter wrote: > > Can we please not nack everything right away? Doesn't really motivate > > me to show you all the various things we're doing in gpu to make the > > dma layer work for us. That kind of noodling around in lower levels to > > get them to do what we want is absolutely par-for-course for gpu > > drivers. If you just nack everything I point you at for illustrative > > purposes, then I can't show you stuff anymore. > > No, it's not. No driver (and that includes the magic GPUs) has > any business messing with dma ops directly. > > A GPU driver imght have a very valid reason to disable the IOMMU, > but the code to do so needs to be at least in the arch code, maybe > in the dma-mapping/iommu code, not in the driver. > > As a first step to get the discussion started we'll simply need > to move the code Thierry wrote into a helper in arch/arm and that > alone would be a massive improvement. I'm not even talking about > minor details like actually using arm_get_dma_map_ops instead > of duplicating it. > > And doing this basic trivial work really helps to get this whole > mess under control. Ah ok. It did sound a bit like a much more cathegorical NAK than an "ack in principle, but we need to shuffle the implementation into the right place first". In the past we generally got a principled NAK on anything funny we've been doing with the dma api, and the dma api maintainer steaming off telling us we're incompetent idiots. I guess I've been branded a bit on this topic :-/ Really great that this is changing now. On the patch itself: It might not be the right thing in all cases, since for certain compression formats the nv gpu wants larger pages (easy to allocate from vram, not so easy from main memory), so might need the iommu still. But currently that's not implemented: https://www.spinics.net/lists/dri-devel/msg173932.html Cheers, Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Vetter Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag Date: Wed, 25 Apr 2018 09:30:39 +0200 Message-ID: <20180425073039.GO25142@phenom.ffwll.local> References: <20180420124625.GA31078@infradead.org> <20180420152111.GR31310@phenom.ffwll.local> <20180424184847.GA3247@infradead.org> <20180425054855.GA17038@infradead.org> <20180425064335.GB28100@infradead.org> <20180425070905.GA24827@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20180425070905.GA24827-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: amd-gfx-bounces-PD4FTy7X32lNgt0PjOBp9y5qC8QIuHrW@public.gmane.org Sender: "amd-gfx" To: Christoph Hellwig Cc: Linux Kernel Mailing List , amd-gfx list , "moderated list:DMA BUFFER SHARING FRAMEWORK" , Jerome Glisse , dri-devel , Daniel Vetter , Dan Williams , Thierry Reding , Logan Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , "open list:DMA BUFFER SHARING FRAMEWORK" List-Id: dri-devel@lists.freedesktop.org T24gV2VkLCBBcHIgMjUsIDIwMTggYXQgMTI6MDk6MDVBTSAtMDcwMCwgQ2hyaXN0b3BoIEhlbGx3 aWcgd3JvdGU6Cj4gT24gV2VkLCBBcHIgMjUsIDIwMTggYXQgMDk6MDI6MTdBTSArMDIwMCwgRGFu aWVsIFZldHRlciB3cm90ZToKPiA+IENhbiB3ZSBwbGVhc2Ugbm90IG5hY2sgZXZlcnl0aGluZyBy aWdodCBhd2F5PyBEb2Vzbid0IHJlYWxseSBtb3RpdmF0ZQo+ID4gbWUgdG8gc2hvdyB5b3UgYWxs IHRoZSB2YXJpb3VzIHRoaW5ncyB3ZSdyZSBkb2luZyBpbiBncHUgdG8gbWFrZSB0aGUKPiA+IGRt YSBsYXllciB3b3JrIGZvciB1cy4gVGhhdCBraW5kIG9mIG5vb2RsaW5nIGFyb3VuZCBpbiBsb3dl ciBsZXZlbHMgdG8KPiA+IGdldCB0aGVtIHRvIGRvIHdoYXQgd2Ugd2FudCBpcyBhYnNvbHV0ZWx5 IHBhci1mb3ItY291cnNlIGZvciBncHUKPiA+IGRyaXZlcnMuIElmIHlvdSBqdXN0IG5hY2sgZXZl cnl0aGluZyBJIHBvaW50IHlvdSBhdCBmb3IgaWxsdXN0cmF0aXZlCj4gPiBwdXJwb3NlcywgdGhl biBJIGNhbid0IHNob3cgeW91IHN0dWZmIGFueW1vcmUuCj4gCj4gTm8sIGl0J3Mgbm90LiAgTm8g ZHJpdmVyIChhbmQgdGhhdCBpbmNsdWRlcyB0aGUgbWFnaWMgR1BVcykgaGFzCj4gYW55IGJ1c2lu ZXNzIG1lc3Npbmcgd2l0aCBkbWEgb3BzIGRpcmVjdGx5Lgo+IAo+IEEgR1BVIGRyaXZlciBpbWdo dCBoYXZlIGEgdmVyeSB2YWxpZCByZWFzb24gdG8gZGlzYWJsZSB0aGUgSU9NTVUsCj4gYnV0IHRo ZSBjb2RlIHRvIGRvIHNvIG5lZWRzIHRvIGJlIGF0IGxlYXN0IGluIHRoZSBhcmNoIGNvZGUsIG1h eWJlCj4gaW4gdGhlIGRtYS1tYXBwaW5nL2lvbW11IGNvZGUsIG5vdCBpbiB0aGUgZHJpdmVyLgo+ IAo+IEFzIGEgZmlyc3Qgc3RlcCB0byBnZXQgdGhlIGRpc2N1c3Npb24gc3RhcnRlZCB3ZSdsbCBz aW1wbHkgbmVlZAo+IHRvIG1vdmUgdGhlIGNvZGUgVGhpZXJyeSB3cm90ZSBpbnRvIGEgaGVscGVy IGluIGFyY2gvYXJtIGFuZCB0aGF0Cj4gYWxvbmUgd291bGQgYmUgYSBtYXNzaXZlIGltcHJvdmVt ZW50LiAgSSdtIG5vdCBldmVuIHRhbGtpbmcgYWJvdXQKPiBtaW5vciBkZXRhaWxzIGxpa2UgYWN0 dWFsbHkgdXNpbmcgYXJtX2dldF9kbWFfbWFwX29wcyBpbnN0ZWFkCj4gb2YgZHVwbGljYXRpbmcg aXQuCj4gCj4gQW5kIGRvaW5nIHRoaXMgYmFzaWMgdHJpdmlhbCB3b3JrIHJlYWxseSBoZWxwcyB0 byBnZXQgdGhpcyB3aG9sZQo+IG1lc3MgdW5kZXIgY29udHJvbC4KCkFoIG9rLiBJdCBkaWQgc291 bmQgYSBiaXQgbGlrZSBhIG11Y2ggbW9yZSBjYXRoZWdvcmljYWwgTkFLIHRoYW4gYW4gImFjawpp biBwcmluY2lwbGUsIGJ1dCB3ZSBuZWVkIHRvIHNodWZmbGUgdGhlIGltcGxlbWVudGF0aW9uIGlu dG8gdGhlIHJpZ2h0CnBsYWNlIGZpcnN0Ii4gSW4gdGhlIHBhc3Qgd2UgZ2VuZXJhbGx5IGdvdCBh IHByaW5jaXBsZWQgTkFLIG9uIGFueXRoaW5nCmZ1bm55IHdlJ3ZlIGJlZW4gZG9pbmcgd2l0aCB0 aGUgZG1hIGFwaSwgYW5kIHRoZSBkbWEgYXBpIG1haW50YWluZXIKc3RlYW1pbmcgb2ZmIHRlbGxp bmcgdXMgd2UncmUgaW5jb21wZXRlbnQgaWRpb3RzLiBJIGd1ZXNzIEkndmUgYmVlbgpicmFuZGVk IGEgYml0IG9uIHRoaXMgdG9waWMgOi0vCgpSZWFsbHkgZ3JlYXQgdGhhdCB0aGlzIGlzIGNoYW5n aW5nIG5vdy4KCk9uIHRoZSBwYXRjaCBpdHNlbGY6IEl0IG1pZ2h0IG5vdCBiZSB0aGUgcmlnaHQg dGhpbmcgaW4gYWxsIGNhc2VzLCBzaW5jZQpmb3IgY2VydGFpbiBjb21wcmVzc2lvbiBmb3JtYXRz IHRoZSBudiBncHUgd2FudHMgbGFyZ2VyIHBhZ2VzIChlYXN5IHRvCmFsbG9jYXRlIGZyb20gdnJh bSwgbm90IHNvIGVhc3kgZnJvbSBtYWluIG1lbW9yeSksIHNvIG1pZ2h0IG5lZWQgdGhlIGlvbW11 CnN0aWxsLiBCdXQgY3VycmVudGx5IHRoYXQncyBub3QgaW1wbGVtZW50ZWQ6CgpodHRwczovL3d3 dy5zcGluaWNzLm5ldC9saXN0cy9kcmktZGV2ZWwvbXNnMTczOTMyLmh0bWwKCkNoZWVycywgRGFu aWVsCi0tIApEYW5pZWwgVmV0dGVyClNvZnR3YXJlIEVuZ2luZWVyLCBJbnRlbCBDb3Jwb3JhdGlv bgpodHRwOi8vYmxvZy5mZndsbC5jaApfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fXwphbWQtZ2Z4IG1haWxpbmcgbGlzdAphbWQtZ2Z4QGxpc3RzLmZyZWVkZXNr dG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZvL2Ft ZC1nZngK