Closed Bug 1588907 Opened 3 months ago Closed 3 months ago

[Wayland] Bracket CPU read/write sequences by DMA_BUF_IOCTL_SYNC

Categories

(Core :: Widget: Gtk, enhancement)

enhancement
Not set

Tracking

()

RESOLVED FIXED
mozilla71
Tracking Status
firefox71 --- fixed

People

(Reporter: stransky, Assigned: stransky)

References

(Blocks 1 open bug)

Details

Attachments

(1 file)

Pekka Paalanen at wayland-devel list about dma buf access:

Lock/Unlock:
An important detail is that you must use DMA_BUF_IOCTL_SYNC to
bracket your actual CPU read/write sequences to the dmabuf. That ioctl
will ensure the appropriate caches are flushed correctly (you might not
notice anything wrong on x86, but on other hardware forgetting to do
that can randomly result in bad data), and I think it also waits for
implicit fences (e.g. if you had GPU write to the dmabuf earlier, to
ensure the operation finished).

Looks like we don't need that as far as we use gbm_bo_map() instead of mmap().

Assignee: nobody → stransky
Keywords: checkin-needed

Pushed by btara@mozilla.com:
https://hg.mozilla.org/integration/autoland/rev/bec939498aa9
[Wayland] Remove misleading comment about DMA_BUF_IOCTL_SYNC, r=jhorak

Keywords: checkin-needed
Status: NEW → RESOLVED
Closed: 3 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla71
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