Why we didn't use embedded gem object for virtio gpu when making ttm bo a gem bo subclass?
Hi Gerd,
We found a bug in 5.4 kernel and virtgpu_gem_prime_mmap doesn't work because it references vma_node in gem_base object while ttm code initialized vma_node in tbo.base object. I am wondering, in your original serial: https://patchwork.kernel.org/project/dri-devel/cover/20190805124310.3275-1-k... (drm/ttm: make ttm bo a gem bo subclass), why you changed to use embedded gem object for most gpu drivers but skipping virtio gpu? Is there some specific reason?
I am thinking about CL like this (http://crrev.com/c/3092457) to fix it and not sure if I missed something.
Thanks for your help!
On Fri, Aug 13, 2021 at 12:42:51PM -0700, lepton wrote:
Hi Gerd,
We found a bug in 5.4 kernel and virtgpu_gem_prime_mmap doesn't work because it references vma_node in gem_base object while ttm code initialized vma_node in tbo.base object. I am wondering, in your original serial: https://patchwork.kernel.org/project/dri-devel/cover/20190805124310.3275-1-k... (drm/ttm: make ttm bo a gem bo subclass), why you changed to use embedded gem object for most gpu drivers but skipping virtio gpu? Is there some specific reason?
commit c66df701e783bc666593e6e665f13670760883ee Author: Gerd Hoffmann kraxel@redhat.com Date: Thu Aug 29 12:32:57 2019 +0200
drm/virtio: switch from ttm to gem shmem helpers
HTH, Gerd
Hi Gerd,
Thanks for your reply. I was aware of that change, but need a fix for 5.4 kernel as a temp solution for now. If the reason is just that you will move away from ttm soon,then I guess a CL like http://crrev.com/c/3092457 should work for 5.4, just hope I don't miss anything else.
Thanks!
On Sun, Aug 15, 2021 at 9:46 PM Gerd Hoffmann kraxel@redhat.com wrote:
On Fri, Aug 13, 2021 at 12:42:51PM -0700, lepton wrote:
Hi Gerd,
We found a bug in 5.4 kernel and virtgpu_gem_prime_mmap doesn't work because it references vma_node in gem_base object while ttm code initialized vma_node in tbo.base object. I am wondering, in your original serial: https://patchwork.kernel.org/project/dri-devel/cover/20190805124310.3275-1-k... (drm/ttm: make ttm bo a gem bo subclass), why you changed to use embedded gem object for most gpu drivers but skipping virtio gpu? Is there some specific reason?
commit c66df701e783bc666593e6e665f13670760883ee Author: Gerd Hoffmann kraxel@redhat.com Date: Thu Aug 29 12:32:57 2019 +0200
drm/virtio: switch from ttm to gem shmem helpersHTH, Gerd
On Sun, Aug 15, 2021 at 09:51:02PM -0700, lepton wrote:
Hi Gerd,
Thanks for your reply. I was aware of that change, but need a fix for 5.4 kernel as a temp solution for now. If the reason is just that you will move away from ttm soon,then I guess a CL like http://crrev.com/c/3092457 should work for 5.4, just hope I don't miss anything else.
Looks sane on a quick glance.
take care, Gerd
dri-devel@lists.freedesktop.org
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Gerd Hoffmann -
lepton