• Robert Bragg's avatar
    drm/i915: don't whitelist oacontrol in cmd parser · 10ff401d
    Robert Bragg authored
    Being able to program OACONTROL from a non-privileged batch buffer is
    not sufficient to be able to configure the OA unit. This was originally
    allowed to help enable Mesa to expose OA counters via the
    INTEL_performance_query extension, but the current implementation based
    on programming OACONTROL via a batch buffer isn't able to report useable
    data without a more complete OA unit configuration. Mesa handles the
    possibility that writes to OACONTROL may not be allowed and so only
    advertises the extension after explicitly testing that a write to
    OACONTROL succeeds. Based on this; removing OACONTROL from the whitelist
    should be ok for userspace.
    
    Removing this simplifies adding a new kernel api for configuring the OA
    unit without needing to consider the possibility that userspace might
    trample on OACONTROL state which we'd like to start managing within
    the kernel instead. In particular running any Mesa based GL application
    currently results in clearing OACONTROL when initializing which would
    disable the capturing of metrics.
    
    v2:
        This bumps the command parser version from 8 to 9, as the change is
        visible to userspace.
    Signed-off-by: default avatarRobert Bragg <robert@sixbynine.org>
    Reviewed-by: default avatarMatthew Auld <matthew.auld@intel.com>
    Reviewed-by: default avatarSourab Gupta &lt;sourab.gupta@intel.com&gt;Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
    Link: http://patchwork.freedesktop.org/patch/msgid/20161108125148.25007-1-robert@sixbynine.org
    10ff401d
i915_cmd_parser.c 38.7 KB