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Groups > linux.kernel > #1517098
| From | Daniel Vetter <daniel@ffwll.ch> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v7 0/3] drm: add explict fencing |
| Date | 2016-11-08 12:40 +0100 |
| Message-ID | <sBcUW-iC-5@gated-at.bofh.it> (permalink) |
| References | <sB8xX-5U7-7@gated-at.bofh.it> <sBcid-8hA-5@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Tue, Nov 08, 2016 at 10:35:08AM +0000, Chris Wilson wrote: > On Tue, Nov 08, 2016 at 03:54:47PM +0900, Gustavo Padovan wrote: > > From: Gustavo Padovan <gustavo.padovan@collabora.co.uk> > > > > Hi, > > > > This is yet another version of the DRM fences patches. Please refer > > to the cover letter[1] in a previous version to check for more details. > > Explicit fencing is not a superset of the implicit fences. The driver > may be using implicit fences (on a reservation object) to serialise > asynchronous operations wrt to each other (such as dispatching threads > to flush cpu caches to memory, manipulating page tables and the like > before the flip). Since the user doesn't know about these operations, > they are not included in the explicit fence they provide, at which point > we can't trust their fence to the exclusion of the implicit fences... My thoughts are that in atomic_check drivers just fill in the fence from the reservation_object (i.e. the uapi implicit fencing part). If there's any additional work that's queued up in ->prepare_fb then I guess the driver needs to track that internally, but _only_ for kernel-internally queued work. The reason for that is that with explicit fencing we want to allow userspace to overwrite any existing implicit fences that might hang around. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
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[PATCH v7 0/3] drm: add explict fencing Gustavo Padovan <gustavo@padovan.org> - 2016-11-08 08:00 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Chris Wilson <chris@chris-wilson.co.uk> - 2016-11-08 12:00 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Daniel Vetter <daniel@ffwll.ch> - 2016-11-08 12:40 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Chris Wilson <chris@chris-wilson.co.uk> - 2016-11-08 12:50 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Daniel Vetter <daniel@ffwll.ch> - 2016-11-08 13:50 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Chris Wilson <chris@chris-wilson.co.uk> - 2016-11-08 14:00 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Daniel Vetter <daniel@ffwll.ch> - 2016-11-08 14:00 +0100
Re: [PATCH v7 0/3] drm: add explict fencing Daniel Vetter <daniel@ffwll.ch> - 2016-11-08 14:20 +0100
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