From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jason Gunthorpe Subject: Re: [PATCH 15/15] amdgpu: remove CONFIG_DRM_AMDGPU_USERPTR Date: Tue, 6 Aug 2019 17:03:56 -0300 Message-ID: <20190806200356.GU11627@ziepe.ca> References: <20190806160554.14046-1-hch@lst.de> <20190806160554.14046-16-hch@lst.de> <20190806174437.GK11627@ziepe.ca> <587b1c3c-83c4-7de9-242f-6516528049f4@amd.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: Alex Deucher Cc: "Kuehling, Felix" , Christoph Hellwig , "Deucher, Alexander" , "Koenig, Christian" , Ralph Campbell , "amd-gfx@lists.freedesktop.org" , "nouveau@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-mm@kvack.org" , =?utf-8?B?SsOpcsO0bWU=?= Glisse , Ben Skeggs List-Id: dri-devel@lists.freedesktop.org On Tue, Aug 06, 2019 at 02:58:58PM -0400, Alex Deucher wrote: > On Tue, Aug 6, 2019 at 1:51 PM Kuehling, Felix wrote: > > > > On 2019-08-06 13:44, Jason Gunthorpe wrote: > > > On Tue, Aug 06, 2019 at 07:05:53PM +0300, Christoph Hellwig wrote: > > >> The option is just used to select HMM mirror support and has a very > > >> confusing help text. Just pull in the HMM mirror code by default > > >> instead. > > >> > > >> Signed-off-by: Christoph Hellwig > > >> drivers/gpu/drm/Kconfig | 2 ++ > > >> drivers/gpu/drm/amd/amdgpu/Kconfig | 10 ---------- > > >> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 6 ------ > > >> drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.h | 12 ------------ > > >> 4 files changed, 2 insertions(+), 28 deletions(-) > > > Felix, was this an effort to avoid the arch restriction on hmm or > > > something? Also can't see why this was like this. > > > > This option predates KFD's support of userptrs, which in turn predates > > HMM. Radeon has the same kind of option, though it doesn't affect HMM in > > that case. > > > > Alex, Christian, can you think of a good reason to maintain userptr > > support as an option in amdgpu? I suspect it was originally meant as a > > way to allow kernels with amdgpu without MMU notifiers. Now it would > > allow a kernel with amdgpu without HMM or MMU notifiers. I don't know if > > this is a useful thing to have. > > Right. There were people that didn't have MMU notifiers that wanted > support for the GPU. ?? Is that even a real thing? mmu_notifier does not have much kconfig dependency. Jason