[PATCH 2/4] drm/i915/lpt: Avoid early timeout during FDI PHY reset

Imre Deak
2016-06-28T10:37:39Z

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>
---
drivers/gpu/drm/i915/intel_display.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index c3b5dc8..0312472 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -8537,16 +8537,16 @@ static void lpt_reset_fdi_mphy(struct drm_i915_private *dev_priv)
tmp |= FDI_MPHY_IOSFSB_RESET_CTL;
I915_WRITE(SOUTH_CHICKEN2, tmp);

- if (wait_for_atomic_us(I915_READ(SOUTH_CHICKEN2) &
- FDI_MPHY_IOSFSB_RESET_STATUS, 100))
+ if (wait_for_us(I915_READ(SOUTH_CHICKEN2) &
+ FDI_MPHY_IOSFSB_RESET_STATUS, 100))
DRM_ERROR("FDI mPHY reset assert timeout\n");

tmp = I915_READ(SOUTH_CHICKEN2);
tmp &= ~FDI_MPHY_IOSFSB_RESET_CTL;
I915_WRITE(SOUTH_CHICKEN2, tmp);

- if (wait_for_atomic_us((I915_READ(SOUTH_CHICKEN2) &
- FDI_MPHY_IOSFSB_RESET_STATUS) == 0, 100))
+ if (wait_for_us((I915_READ(SOUTH_CHICKEN2) &
+ FDI_MPHY_IOSFSB_RESET_STATUS) == 0, 100))
DRM_ERROR("FDI mPHY reset de-assert timeout\n");
}

--
2.5.0