1. 08 Jun, 2022 2 commits
    • Jason Ekstrand's avatar
      dma-buf: Add an API for exporting sync files (v14) · 20e10881
      Jason Ekstrand authored
      Modern userspace APIs like Vulkan are built on an explicit
      synchronization model.  This doesn't always play nicely with the
      implicit synchronization used in the kernel and assumed by X11 and
      Wayland.  The client -> compositor half of the synchronization isn't too
      bad, at least on intel, because we can control whether or not i915
      synchronizes on the buffer and whether or not it's considered written.
      
      The harder part is the compositor -> client synchronization when we get
      the buffer back from the compositor.  We're required to be able to
      provide the client with a VkSemaphore and VkFence representing the point
      in time where the window system (compositor and/or display) finished
      using the buffer.  With current APIs, it's very hard to do this in such
      a way that we don't get confused by the Vulkan driver's access of the
      buffer.  In particular, once we tell the kernel that we're rendering to
      the buffer again, any CPU waits on the buffer or GPU dependencies will
      wait on some of the client rendering and not just the compositor.
      
      This new IOCTL solves this problem by allowing us to get a snapshot of
      the implicit synchronization state of a given dma-buf in the form of a
      sync file.  It's effectively the same as a poll() or I915_GEM_WAIT only,
      instead of CPU waiting directly, it encapsulates the wait operation, at
      the current moment in time, in a sync_file so we can check/wait on it
      later.  As long as the Vulkan driver does the sync_file export from the
      dma-buf before we re-introduce it for rendering, it will only contain
      fences from the compositor or display.  This allows to accurately turn
      it into a VkFence or VkSemaphore without any over-synchronization.
      
      By making this an ioctl on the dma-buf itself, it allows this new
      functionality to be used in an entirely driver-agnostic way without
      having access to a DRM fd. This makes it ideal for use in driver-generic
      code in Mesa or in a client such as a compositor where the DRM fd may be
      hard to reach.
      
      v2 (Jason Ekstrand):
       - Use a wrapper dma_fence_array of all fences including the new one
         when importing an exclusive fence.
      
      v3 (Jason Ekstrand):
       - Lock around setting shared fences as well as exclusive
       - Mark SIGNAL_SYNC_FILE as a read-write ioctl.
       - Initialize ret to 0 in dma_buf_wait_sync_file
      
      v4 (Jason Ekstrand):
       - Use the new dma_resv_get_singleton helper
      
      v5 (Jason Ekstrand):
       - Rename the IOCTLs to import/export rather than wait/signal
       - Drop the WRITE flag and always get/set the exclusive fence
      
      v6 (Jason Ekstrand):
       - Drop the sync_file import as it was all-around sketchy and not nearly
         as useful as import.
       - Re-introduce READ/WRITE flag support for export
       - Rework the commit message
      
      v7 (Jason Ekstrand):
       - Require at least one sync flag
       - Fix a refcounting bug: dma_resv_get_excl() doesn't take a reference
       - Use _rcu helpers since we're accessing the dma_resv read-only
      
      v8 (Jason Ekstrand):
       - Return -ENOMEM if the sync_file_create fails
       - Predicate support on IS_ENABLED(CONFIG_SYNC_FILE)
      
      v9 (Jason Ekstrand):
       - Add documentation for the new ioctl
      
      v10 (Jason Ekstrand):
       - Go back to dma_buf_sync_file as the ioctl struct name
      
      v11 (Daniel Vetter):
       - Go back to dma_buf_export_sync_file as the ioctl struct name
       - Better kerneldoc describing what the read/write flags do
      
      v12 (Christian König):
       - Document why we chose to make it an ioctl on dma-buf
      
      v13 (Jason Ekstrand):
       - Rebase on Christian König's fence rework
      
      v14 (Daniel Vetter & Christian König):
       - Use dma_rev_usage_rw to get the properly inverted usage to pass to
         dma_resv_get_singleton()
       - Clean up the sync_file and fd if copy_to_user() fails
      Signed-off-by: default avatarJason Ekstrand <jason@jlekstrand.net>
      Signed-off-by: default avatarJason Ekstrand <jason.ekstrand@intel.com>
      Signed-off-by: default avatarJason Ekstrand <jason.ekstrand@collabora.com>
      Acked-by: default avatarSimon Ser <contact@emersion.fr>
      Reviewed-by: default avatarChristian König <christian.koenig@amd.com>
      Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
      Cc: Sumit Semwal <sumit.semwal@linaro.org>
      Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
      Signed-off-by: default avatarSimon Ser <contact@emersion.fr>
      Link: https://patchwork.freedesktop.org/patch/msgid/20220608152142.14495-2-jason@jlekstrand.net
      20e10881
    • Thomas Zimmermann's avatar
      drm/ast: Support multiple outputs · 7f35680a
      Thomas Zimmermann authored
      Systems with AST graphics can have multiple output; typically VGA
      plus some other port. Record detected output chips in a bitmask and
      initialize each output on its own.
      
      Assume a VGA output by default and use SIL164 and DP501 if available.
      For ASTDP assume that it can run in parallel with VGA.
      
      Tested on AST2100.
      
      v3:
      	* define a macro for each BIT(ast_tx_chip) (Patrik)
      v2:
      	* make VGA/SIL164/DP501 mutually exclusive
      Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
      Reviewed-by: default avatarPatrik Jakobsson <patrik.r.jakobsson@gmail.com>
      Fixes: a59b0264 ("drm/ast: Initialize encoder and connector for VGA in helper function")
      Cc: Thomas Zimmermann <tzimmermann@suse.de>
      Cc: Javier Martinez Canillas <javierm@redhat.com>
      Cc: Dave Airlie <airlied@redhat.com>
      Cc: dri-devel@lists.freedesktop.org
      Link: https://patchwork.freedesktop.org/patch/msgid/20220607092008.22123-2-tzimmermann@suse.de
      7f35680a
  2. 07 Jun, 2022 13 commits
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  8. 30 May, 2022 8 commits