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* [Intel-gfx] [PATCH 0/2] drm/i915/gem: dma-buf fixes for migration
@ 2021-06-30 13:06 Thomas Hellström
  2021-06-30 13:07 ` [Intel-gfx] [PATCH 1/2] drm/i915/gem: Make our dma-buf exporter dynamic Thomas Hellström
                   ` (3 more replies)
  0 siblings, 4 replies; 8+ messages in thread
From: Thomas Hellström @ 2021-06-30 13:06 UTC (permalink / raw)
  To: intel-gfx, dri-devel; +Cc: Thomas Hellström, matthew.auld

Our dma-buf code is currently completely broken unless the importer is
dynamic in which case the sg_list caching saves the day. In particular,
the case where another instance of our driver tries to import a dma-buf
exported by our driver ends up in a recursive lock.

Since the recent TTM migration work spec specifies to fix up the dma-buf
code with migration and there's no point in doing so when it's
completely broken, take a first step to make at least the exporter obey
the dma-buf locking rules the dma-buf core enforces for a dynamic exporter:

- Implement and act on pin- and unpin.
- Call move_notify if migrating. (we opt not to migrate while dma-buf_mapped).
- map_dma_buf() is unconditionally called locked.

Add a selftest that ensures that it works with both our own and a fake
dynamic importer.

Also implement migration in the second patch before pinning in pin()
and map_dma_buf().

Note that the importer remains broken for other non-dynamic exporters, but
at least not for the same-driver-separate-instances case.

Regardless whether we want to fix this now with this series, or in an
unspecified future, the selftest may come in handy.

Thomas Hellström (2):
  drm/i915/gem: Make our dma-buf exporter dynamic
  drm/i915/gem: Migrate to system at dma-buf map time

 drivers/gpu/drm/i915/gem/i915_gem_dmabuf.c    |  48 ++++++-
 .../drm/i915/gem/selftests/i915_gem_dmabuf.c  | 118 +++++++++++++++++-
 2 files changed, 162 insertions(+), 4 deletions(-)

-- 
2.31.1

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^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-06-30 18:15 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2021-06-30 13:06 [Intel-gfx] [PATCH 0/2] drm/i915/gem: dma-buf fixes for migration Thomas Hellström
2021-06-30 13:07 ` [Intel-gfx] [PATCH 1/2] drm/i915/gem: Make our dma-buf exporter dynamic Thomas Hellström
2021-06-30 14:01   ` Daniel Vetter
2021-06-30 14:06     ` Ruhl, Michael J
2021-06-30 17:14     ` Daniel Vetter
2021-06-30 13:07 ` [Intel-gfx] [PATCH 2/2] drm/i915/gem: Migrate to system at dma-buf map time Thomas Hellström
2021-06-30 17:46 ` [Intel-gfx] ✗ Fi.CI.CHECKPATCH: warning for drm/i915/gem: dma-buf fixes for migration Patchwork
2021-06-30 18:15 ` [Intel-gfx] ✗ Fi.CI.BAT: failure " Patchwork

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