drm/i915/perf: Clear out entire reports after reading if not power of 2 size
authorAshutosh Dixit <ashutosh.dixit@intel.com>
Tue, 23 May 2023 20:40:42 +0000 (13:40 -0700)
committerAshutosh Dixit <ashutosh.dixit@intel.com>
Wed, 31 May 2023 20:18:38 +0000 (13:18 -0700)
commit09a36015d9a0940214c080f95afc605c47648bbd
treeb2ecda5ecd3b26e51a4b99a0b98317d57ee58e88
parent84596e1ab09a2a2d4d4898444c01ca08b64cb7bd
drm/i915/perf: Clear out entire reports after reading if not power of 2 size

Clearing out report id and timestamp as means to detect unlanded reports
only works if report size is power of 2. That is, only when report size is
a sub-multiple of the OA buffer size can we be certain that reports will
land at the same place each time in the OA buffer (after rewind). If report
size is not a power of 2, we need to zero out the entire report to be able
to detect unlanded reports reliably.

v2: Add Fixes tag (Umesh)

Fixes: 1cc064dce4ed ("drm/i915/perf: Add support for OA media units")
Reviewed-by: Umesh Nerlige Ramappa <umesh.nerlige.ramappa@intel.com>
Reviewed-by: Lionel Landwerlin <lionel.g.landwerlin@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230523204042.4180641-1-ashutosh.dixit@intel.com
drivers/gpu/drm/i915/i915_perf.c