diff options
Diffstat (limited to 'drivers/gpu/drm/i915/intel_dp.c')
| -rw-r--r-- | drivers/gpu/drm/i915/intel_dp.c | 37 |
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 df648cb4c29..864417cffe9 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 |