From mboxrd@z Thu Jan 1 00:00:00 1970 From: Christoph Hellwig Subject: Re: [PATCH 2/8] PCI: Add pci_find_common_upstream_dev() Date: Thu, 29 Mar 2018 23:33:34 -0700 Message-ID: <20180330063334.GA8634@infradead.org> References: <16c7bef8-5f03-9e89-1f50-b62fb139a36f@deltatee.com> <6a5c9a10-50fe-b03d-dfc1-791d62d79f8e@amd.com> <73578b4e-664b-141c-3e1f-e1fae1e4db07@amd.com> <1b08c13e-b4a2-08f2-6194-93e6c21b7965@deltatee.com> <70adc2cc-f7aa-d4b9-7d7a-71f3ae99f16c@gmail.com> <98ce6cfd-bcf3-811e-a0f1-757b60da467a@deltatee.com> <8d050848-8970-b8c4-a657-429fefd31769@amd.com> <20180330015854.GA3572@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20180330015854.GA3572@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" To: Jerome Glisse Cc: linaro-mm-sig@lists.linaro.org, linux-kernel@vger.kernel.org, amd-gfx@lists.freedesktop.org, Christoph Hellwig , dri-devel@lists.freedesktop.org, Bjorn Helgaas , Logan Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , linux-media@vger.kernel.org List-Id: amd-gfx.lists.freedesktop.org T24gVGh1LCBNYXIgMjksIDIwMTggYXQgMDk6NTg6NTRQTSAtMDQwMCwgSmVyb21lIEdsaXNzZSB3 cm90ZToKPiBkbWFfbWFwX3Jlc291cmNlKCkgaXMgdGhlIHJpZ2h0IEFQSSAodGhvdWdodCBpdHMg Y3VycmVudCBpbXBsZW1lbnRhdGlvbgo+IGlzIGZpbGwgd2l0aCB4ODYgYXNzdW1wdGlvbnMpLiBT byBpIHdvdWxkIGFyZ3VlIHRoYXQgYXJjaCBjYW4gZGVjaWRlIHRvCj4gaW1wbGVtZW50IGl0IG9y IHNpbXBseSByZXR1cm4gZG1hIGVycm9yIGFkZHJlc3Mgd2hpY2ggdHJpZ2dlciBmYWxsYmFjawo+ IHBhdGggaW50byB0aGUgY2FsbGVyIChhdCBsZWFzdCBmb3IgR1BVIGRyaXZlcnMpLiBTRyB2YXJp YW50IGNhbiBiZSBhZGRlZAo+IG9uIHRvcC4KCkl0IGlzbid0IGluIGdlbmVyYWwuICBJdCBkb2Vz bid0IGludGVncmF0ZSB3aXRoIHNjYXR0ZXJsaXN0cyAoc2VlIG15CmNvbW1lbnQgdG8gcGFnZSBv bmUpLCBhbmQgaXQgZG9lc24ndCBpbnRlZ3JhdGUgd2l0aCBhbGwgdGhlIHN1YnN5c3RlbXMKdGhh dCBhbHNvIG5lZWQgYSBrZXJuZWwgdmlydHVhbCBhZGRyZXNzLgpfX19fX19fX19fX19fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fXwpkcmktZGV2ZWwgbWFpbGluZyBsaXN0CmRyaS1k ZXZlbEBsaXN0cy5mcmVlZGVza3RvcC5vcmcKaHR0cHM6Ly9saXN0cy5mcmVlZGVza3RvcC5vcmcv bWFpbG1hbi9saXN0aW5mby9kcmktZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from bombadil.infradead.org ([198.137.202.133]:34000 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750764AbeC3Gdn (ORCPT ); Fri, 30 Mar 2018 02:33:43 -0400 Date: Thu, 29 Mar 2018 23:33:34 -0700 From: Christoph Hellwig To: Jerome Glisse Cc: Logan Gunthorpe , Christian =?iso-8859-1?Q?K=F6nig?= , Christoph Hellwig , linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-media@vger.kernel.org, Bjorn Helgaas Subject: Re: [PATCH 2/8] PCI: Add pci_find_common_upstream_dev() Message-ID: <20180330063334.GA8634@infradead.org> References: <16c7bef8-5f03-9e89-1f50-b62fb139a36f@deltatee.com> <6a5c9a10-50fe-b03d-dfc1-791d62d79f8e@amd.com> <73578b4e-664b-141c-3e1f-e1fae1e4db07@amd.com> <1b08c13e-b4a2-08f2-6194-93e6c21b7965@deltatee.com> <70adc2cc-f7aa-d4b9-7d7a-71f3ae99f16c@gmail.com> <98ce6cfd-bcf3-811e-a0f1-757b60da467a@deltatee.com> <8d050848-8970-b8c4-a657-429fefd31769@amd.com> <20180330015854.GA3572@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180330015854.GA3572@redhat.com> Sender: linux-media-owner@vger.kernel.org List-ID: On Thu, Mar 29, 2018 at 09:58:54PM -0400, Jerome Glisse wrote: > dma_map_resource() is the right API (thought its current implementation > is fill with x86 assumptions). So i would argue that arch can decide to > implement it or simply return dma error address which trigger fallback > path into the caller (at least for GPU drivers). SG variant can be added > on top. It isn't in general. It doesn't integrate with scatterlists (see my comment to page one), and it doesn't integrate with all the subsystems that also need a kernel virtual address.