drm/i915/hsw: Avoid early timeout during LCPLL disable/restore

Since wait_for_atomic doesn't re-check the wait-for condition after
expiry of the timeout it can fail when called from non-atomic context
even if the condition is set correctly before the expiry. Fix this by
using the non-atomic wait_for instead.

Fixes: 0351b93992aa ("drm/i915: Do not lie about atomic timeout granularity")
CC: Chris Wilson <chris@chris-wilson.co.uk>
CC: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
CC: drm-intel-fixes@lists.freedesktop.org
Link: http://patchwork.freedesktop.org/patch/msgid/1467110253-16046-4-git-send-email-imre.deak@intel.com
(cherry picked from commit f53dd63f1119a98a16d1a5a7cb3277a2f1ff483d)
Signed-off-by: Jani Nikula <jani.nikula@intel.com>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a164ea4..04452cf 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9440,8 +9440,8 @@ static void hsw_disable_lcpll(struct drm_i915_private *dev_priv,
                val |= LCPLL_CD_SOURCE_FCLK;
                I915_WRITE(LCPLL_CTL, val);
 
-               if (wait_for_atomic_us(I915_READ(LCPLL_CTL) &
-                                      LCPLL_CD_SOURCE_FCLK_DONE, 1))
+               if (wait_for_us(I915_READ(LCPLL_CTL) &
+                               LCPLL_CD_SOURCE_FCLK_DONE, 1))
                        DRM_ERROR("Switching to FCLK failed\n");
 
                val = I915_READ(LCPLL_CTL);
@@ -9514,8 +9514,8 @@ static void hsw_restore_lcpll(struct drm_i915_private *dev_priv)
                val &= ~LCPLL_CD_SOURCE_FCLK;
                I915_WRITE(LCPLL_CTL, val);
 
-               if (wait_for_atomic_us((I915_READ(LCPLL_CTL) &
-                                       LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
+               if (wait_for_us((I915_READ(LCPLL_CTL) &
+                                LCPLL_CD_SOURCE_FCLK_DONE) == 0, 1))
                        DRM_ERROR("Switching back to LCPLL failed\n");
        }