drm/i915: avoid premature DP AUX timeouts

During DP AUX communication we might time out 1 jiffy too early, because
the calculated expiry jiffy value is one less than needed.

This is only one reason for false DP AUX timeouts. For a complete
solution we also need the following fix, which is now queued for
mainline: http://marc.info/?l=linux-kernel&m=136748515710837&w=2

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=64133

Signed-off-by: Imre Deak <imre.deak@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 3d704b7..70789b1 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -303,7 +303,7 @@ intel_dp_aux_wait_done(struct intel_dp *intel_dp, bool has_aux_irq)
 #define C (((status = I915_READ_NOTRACE(ch_ctl)) & DP_AUX_CH_CTL_SEND_BUSY) == 0)
        if (has_aux_irq)
                done = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
-                                         msecs_to_jiffies(10));
+                                         msecs_to_jiffies_timeout(10));
        else
                done = wait_for_atomic(C, 10) == 0;
        if (!done)

diff --git a/drivers/gpu/drm/i915/intel_i2c.c b/drivers/gpu/drm/i915/intel_i2c.c
index 98cd853..639fe19 100644 (file)
--- a/drivers/gpu/drm/i915/intel_i2c.c
+++ b/drivers/gpu/drm/i915/intel_i2c.c
@@ -263,7 +263,8 @@ gmbus_wait_idle(struct drm_i915_private *dev_priv)
        /* Important: The hw handles only the first bit, so set only one! */
        I915_WRITE(GMBUS4 + reg_offset, GMBUS_IDLE_EN);
 
-       ret = wait_event_timeout(dev_priv->gmbus_wait_queue, C, 10);
+       ret = wait_event_timeout(dev_priv->gmbus_wait_queue, C,
+                                msecs_to_jiffies_timeout(10));
 
        I915_WRITE(GMBUS4 + reg_offset, 0);