Merge branch 'drm-intel-fixes' into drm-intel-next

1 files changed, 30 insertions, 7 deletions

diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index 63101230b78d..1dc60408d5b8 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -479,6 +479,7 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
         uint16_t address = algo_data->address;
         uint8_t msg[5];
         uint8_t reply[2];
+        unsigned retry;
         int msg_bytes;
         int reply_bytes;
         int ret;
@@ -513,14 +514,33 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
                 break;
         }
 
-        for (;;) {
-          ret = intel_dp_aux_ch(intel_dp,
-                                msg, msg_bytes,
-                                reply, reply_bytes);
+        for (retry = 0; retry < 5; retry++) {
+                ret = intel_dp_aux_ch(intel_dp,
+                                      msg, msg_bytes,
+                                      reply, reply_bytes);
                 if (ret < 0) {
                         DRM_DEBUG_KMS("aux_ch failed %d\n", ret);
                         return ret;
                 }
+
+                switch (reply[0] & AUX_NATIVE_REPLY_MASK) {
+                case AUX_NATIVE_REPLY_ACK:
+                        /* I2C-over-AUX Reply field is only valid
+                         * when paired with AUX ACK.
+                         */
+                        break;
+                case AUX_NATIVE_REPLY_NACK:
+                        DRM_DEBUG_KMS("aux_ch native nack\n");
+                        return -EREMOTEIO;
+                case AUX_NATIVE_REPLY_DEFER:
+                        udelay(100);
+                        continue;
+                default:
+                        DRM_ERROR("aux_ch invalid native reply 0x%02x\n",
+                                  reply[0]);
+                        return -EREMOTEIO;
+                }
+
                 switch (reply[0] & AUX_I2C_REPLY_MASK) {
                 case AUX_I2C_REPLY_ACK:
                         if (mode == MODE_I2C_READ) {
@@ -528,17 +548,20 @@ intel_dp_i2c_aux_ch(struct i2c_adapter *adapter, int mode,
                         }
                         return reply_bytes - 1;
                 case AUX_I2C_REPLY_NACK:
-                        DRM_DEBUG_KMS("aux_ch nack\n");
+                        DRM_DEBUG_KMS("aux_i2c nack\n");
                         return -EREMOTEIO;
                 case AUX_I2C_REPLY_DEFER:
-                        DRM_DEBUG_KMS("aux_ch defer\n");
+                        DRM_DEBUG_KMS("aux_i2c defer\n");
                         udelay(100);
                         break;
                 default:
-                        DRM_ERROR("aux_ch invalid reply 0x%02x\n", reply[0]);
+                        DRM_ERROR("aux_i2c invalid reply 0x%02x\n", reply[0]);
                         return -EREMOTEIO;
                 }
         }
+
+        DRM_ERROR("too many retries, giving up\n");
+        return -EREMOTEIO;
 }
 
 static int