From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751495AbeDYHJK (ORCPT ); Wed, 25 Apr 2018 03:09:10 -0400 Received: from bombadil.infradead.org ([198.137.202.133]:54060 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750941AbeDYHJH (ORCPT ); Wed, 25 Apr 2018 03:09:07 -0400 Date: Wed, 25 Apr 2018 00:09:05 -0700 From: Christoph Hellwig To: Daniel Vetter Cc: 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 Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag Message-ID: <20180425070905.GA24827@infradead.org> References: <20180420124625.GA31078@infradead.org> <20180420152111.GR31310@phenom.ffwll.local> <20180424184847.GA3247@infradead.org> <20180425054855.GA17038@infradead.org> <20180425064335.GB28100@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.2 (2017-12-15) X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [Linaro-mm-sig] [PATCH 4/8] dma-buf: add peer2peer flag Date: Wed, 25 Apr 2018 00:09:05 -0700 Message-ID: <20180425070905.GA24827@infradead.org> References: <20180420124625.GA31078@infradead.org> <20180420152111.GR31310@phenom.ffwll.local> <20180424184847.GA3247@infradead.org> <20180425054855.GA17038@infradead.org> <20180425064335.GB28100@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: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Daniel Vetter Cc: "moderated list:DMA BUFFER SHARING FRAMEWORK" , Linux Kernel Mailing List , amd-gfx list , Christoph Hellwig , Jerome Glisse , dri-devel , 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 T24gV2VkLCBBcHIgMjUsIDIwMTggYXQgMDk6MDI6MTdBTSArMDIwMCwgRGFuaWVsIFZldHRlciB3 cm90ZToKPiBDYW4gd2UgcGxlYXNlIG5vdCBuYWNrIGV2ZXJ5dGhpbmcgcmlnaHQgYXdheT8gRG9l c24ndCByZWFsbHkgbW90aXZhdGUKPiBtZSB0byBzaG93IHlvdSBhbGwgdGhlIHZhcmlvdXMgdGhp bmdzIHdlJ3JlIGRvaW5nIGluIGdwdSB0byBtYWtlIHRoZQo+IGRtYSBsYXllciB3b3JrIGZvciB1 cy4gVGhhdCBraW5kIG9mIG5vb2RsaW5nIGFyb3VuZCBpbiBsb3dlciBsZXZlbHMgdG8KPiBnZXQg dGhlbSB0byBkbyB3aGF0IHdlIHdhbnQgaXMgYWJzb2x1dGVseSBwYXItZm9yLWNvdXJzZSBmb3Ig Z3B1Cj4gZHJpdmVycy4gSWYgeW91IGp1c3QgbmFjayBldmVyeXRoaW5nIEkgcG9pbnQgeW91IGF0 IGZvciBpbGx1c3RyYXRpdmUKPiBwdXJwb3NlcywgdGhlbiBJIGNhbid0IHNob3cgeW91IHN0dWZm IGFueW1vcmUuCgpObywgaXQncyBub3QuICBObyBkcml2ZXIgKGFuZCB0aGF0IGluY2x1ZGVzIHRo ZSBtYWdpYyBHUFVzKSBoYXMKYW55IGJ1c2luZXNzIG1lc3Npbmcgd2l0aCBkbWEgb3BzIGRpcmVj dGx5LgoKQSBHUFUgZHJpdmVyIGltZ2h0IGhhdmUgYSB2ZXJ5IHZhbGlkIHJlYXNvbiB0byBkaXNh YmxlIHRoZSBJT01NVSwKYnV0IHRoZSBjb2RlIHRvIGRvIHNvIG5lZWRzIHRvIGJlIGF0IGxlYXN0 IGluIHRoZSBhcmNoIGNvZGUsIG1heWJlCmluIHRoZSBkbWEtbWFwcGluZy9pb21tdSBjb2RlLCBu b3QgaW4gdGhlIGRyaXZlci4KCkFzIGEgZmlyc3Qgc3RlcCB0byBnZXQgdGhlIGRpc2N1c3Npb24g c3RhcnRlZCB3ZSdsbCBzaW1wbHkgbmVlZAp0byBtb3ZlIHRoZSBjb2RlIFRoaWVycnkgd3JvdGUg aW50byBhIGhlbHBlciBpbiBhcmNoL2FybSBhbmQgdGhhdAphbG9uZSB3b3VsZCBiZSBhIG1hc3Np dmUgaW1wcm92ZW1lbnQuICBJJ20gbm90IGV2ZW4gdGFsa2luZyBhYm91dAptaW5vciBkZXRhaWxz IGxpa2UgYWN0dWFsbHkgdXNpbmcgYXJtX2dldF9kbWFfbWFwX29wcyBpbnN0ZWFkCm9mIGR1cGxp Y2F0aW5nIGl0LgoKQW5kIGRvaW5nIHRoaXMgYmFzaWMgdHJpdmlhbCB3b3JrIHJlYWxseSBoZWxw cyB0byBnZXQgdGhpcyB3aG9sZQptZXNzIHVuZGVyIGNvbnRyb2wuCl9fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmRyaS1kZXZlbCBtYWlsaW5nIGxpc3QKZHJp LWRldmVsQGxpc3RzLmZyZWVkZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9y Zy9tYWlsbWFuL2xpc3RpbmZvL2RyaS1kZXZlbAo=