From 6976e74b5fa12430b36c3b0f8afd7e8e695be0ab Mon Sep 17 00:00:00 2001 From: Michal Wajdeczko Date: Mon, 10 Apr 2017 12:17:47 +0000 Subject: [PATCH] drm/i915: Don't allow overuse of __intel_wait_for_register_fw() This function should not be called with long timeouts in atomic context. Annotate it as might_sleep if timeout is longer than 10us. v2: fix comment (Michal) Signed-off-by: Michal Wajdeczko Suggested-by: Chris Wilson Cc: Chris Wilson Link: http://patchwork.freedesktop.org/patch/msgid/20170410121747.209200-1-michal.wajdeczko@intel.com Reviewed-by: Chris Wilson Signed-off-by: Chris Wilson --- drivers/gpu/drm/i915/intel_uncore.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c index 1deb1a4342ba..eb38392a2435 100644 --- a/drivers/gpu/drm/i915/intel_uncore.c +++ b/drivers/gpu/drm/i915/intel_uncore.c @@ -1600,6 +1600,8 @@ static int gen6_reset_engines(struct drm_i915_private *dev_priv, * (I915_READ_FW(reg) & mask) == value * * Otherwise, the wait will timeout after @slow_timeout_ms milliseconds. + * For atomic context @slow_timeout_ms must be zero and @fast_timeout_us + * must be not larger than 10 microseconds. * * Note that this routine assumes the caller holds forcewake asserted, it is * not suitable for very long waits. See intel_wait_for_register() if you @@ -1620,6 +1622,9 @@ int __intel_wait_for_register_fw(struct drm_i915_private *dev_priv, #define done (((reg_value = I915_READ_FW(reg)) & mask) == value) int ret; + /* Catch any overuse of this function */ + might_sleep_if(fast_timeout_us > 10 || slow_timeout_ms); + if (fast_timeout_us > 10) ret = _wait_for(done, fast_timeout_us, 10); else -- 2.20.1