Since we may lose the content of any buffer when we relinquish control of the system (e.g. suspend/resume), we have to be careful not to rely on regaining control. A good method to detect when we might be using garbage is by always injecting that garbage prior to first use on load/resume/etc.
Suggested-by: Tvrtko Ursulin <[email protected]> Signed-off-by: Chris Wilson <[email protected]> Cc: Tvrtko Ursulin <[email protected]> --- drivers/gpu/drm/i915/gt/intel_lrc.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/drivers/gpu/drm/i915/gt/intel_lrc.c b/drivers/gpu/drm/i915/gt/intel_lrc.c index 34f67eb9bfa1..e8463945024b 100644 --- a/drivers/gpu/drm/i915/gt/intel_lrc.c +++ b/drivers/gpu/drm/i915/gt/intel_lrc.c @@ -3649,6 +3649,18 @@ static void reset_csb_pointers(struct intel_engine_cs *engine) static void execlists_sanitize(struct intel_engine_cs *engine) { + /* + * Poison residual state on resume, in case the suspend didn't! + * + * We have to assume that across suspend/resume (or other loss + * of control) that the contents of our pinned buffers has been + * lost, replaced by garbage. Since this doesn't always happen, + * let's poison such state so that we more quickly spot when + * we falsely assume it has been preserved. + */ + if (IS_ENABLED(CONFIG_DRM_I915_DEBUG_GEM)) + memset(engine->status_page.addr, POISON_INUSE, PAGE_SIZE); + reset_csb_pointers(engine); } -- 2.20.1 _______________________________________________ Intel-gfx mailing list [email protected] https://lists.freedesktop.org/mailman/listinfo/intel-gfx
