drm/i915/dp: increase native aux defer retry timeout

commit 04eada25d1f72efdecd32d702706594f81de65d5 upstream.

Give more slack to sink devices before retrying on native aux
defer. AFAICT the 100 us timeout was not based on the DP spec.

Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 72163e8..39849a9 100644 (file)
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -500,7 +500,7 @@ intel_dp_aux_native_write(struct intel_dp *intel_dp,
                if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_ACK)
                        break;
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
-                       udelay(100);
+                       usleep_range(400, 500);
                else
                        return -EIO;
        }
@@ -549,7 +549,7 @@ intel_dp_aux_native_read(struct intel_dp *intel_dp,
                        return ret - 1;
                }
                else if ((ack & AUX_NATIVE_REPLY_MASK) == AUX_NATIVE_REPLY_DEFER)
-                       udelay(100);
+                       usleep_range(400, 500);
                else
                        return -EIO;
        }