diff options
Diffstat (limited to 'drivers/gpu/drm/drm_dp_helper.c')
| -rw-r--r-- | drivers/gpu/drm/drm_dp_helper.c | 77 |
1 files changed, 52 insertions, 25 deletions
diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c index 7d58f594cffe..eeaf5a7c3aa7 100644 --- a/drivers/gpu/drm/drm_dp_helper.c +++ b/drivers/gpu/drm/drm_dp_helper.c @@ -178,8 +178,8 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, unsigned int offset, void *buffer, size_t size) { struct drm_dp_aux_msg msg; - unsigned int retry; - int err; + unsigned int retry, native_reply; + int err = 0, ret = 0; memset(&msg, 0, sizeof(msg)); msg.address = offset; @@ -187,6 +187,8 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, msg.buffer = buffer; msg.size = size; + mutex_lock(&aux->hw_mutex); + /* * The specification doesn't give any recommendation on how often to * retry native transactions. We used to retry 7 times like for @@ -194,35 +196,39 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, * sufficient, bump to 32 which makes Dell 4k monitors happier. */ for (retry = 0; retry < 32; retry++) { - - mutex_lock(&aux->hw_mutex); - err = aux->transfer(aux, &msg); - mutex_unlock(&aux->hw_mutex); - if (err < 0) { - if (err == -EBUSY) - continue; - - return err; + if (ret != 0 && ret != -ETIMEDOUT) { + usleep_range(AUX_RETRY_INTERVAL, + AUX_RETRY_INTERVAL + 100); } + ret = aux->transfer(aux, &msg); - switch (msg.reply & DP_AUX_NATIVE_REPLY_MASK) { - case DP_AUX_NATIVE_REPLY_ACK: - if (err < size) - return -EPROTO; - return err; + if (ret > 0) { + native_reply = msg.reply & DP_AUX_NATIVE_REPLY_MASK; + if (native_reply == DP_AUX_NATIVE_REPLY_ACK) { + if (ret == size) + goto unlock; - case DP_AUX_NATIVE_REPLY_NACK: - return -EIO; - - case DP_AUX_NATIVE_REPLY_DEFER: - usleep_range(AUX_RETRY_INTERVAL, AUX_RETRY_INTERVAL + 100); - break; + ret = -EPROTO; + } else + ret = -EIO; } + + /* + * We want the error we return to be the error we received on + * the first transaction, since we may get a different error the + * next time we retry + */ + if (!err) + err = ret; } DRM_DEBUG_KMS("too many retries, giving up\n"); - return -EIO; + ret = err; + +unlock: + mutex_unlock(&aux->hw_mutex); + return ret; } /** @@ -242,6 +248,25 @@ static int drm_dp_dpcd_access(struct drm_dp_aux *aux, u8 request, ssize_t drm_dp_dpcd_read(struct drm_dp_aux *aux, unsigned int offset, void *buffer, size_t size) { + int ret; + + /* + * HP ZR24w corrupts the first DPCD access after entering power save + * mode. Eg. on a read, the entire buffer will be filled with the same + * byte. Do a throw away read to avoid corrupting anything we care + * about. Afterwards things will work correctly until the monitor + * gets woken up and subsequently re-enters power save mode. + * + * The user pressing any button on the monitor is enough to wake it + * up, so there is no particularly good place to do the workaround. + * We just have to do it before any DPCD access and hope that the + * monitor doesn't power down exactly after the throw away read. + */ + ret = drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, DP_DPCD_REV, buffer, + 1); + if (ret != 1) + return ret; + return drm_dp_dpcd_access(aux, DP_AUX_NATIVE_READ, offset, buffer, size); } @@ -544,9 +569,7 @@ static int drm_dp_i2c_do_msg(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg) int max_retries = max(7, drm_dp_i2c_retry_count(msg, dp_aux_i2c_speed_khz)); for (retry = 0, defer_i2c = 0; retry < (max_retries + defer_i2c); retry++) { - mutex_lock(&aux->hw_mutex); ret = aux->transfer(aux, msg); - mutex_unlock(&aux->hw_mutex); if (ret < 0) { if (ret == -EBUSY) continue; @@ -685,6 +708,8 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, memset(&msg, 0, sizeof(msg)); + mutex_lock(&aux->hw_mutex); + for (i = 0; i < num; i++) { msg.address = msgs[i].addr; drm_dp_i2c_msg_set_request(&msg, &msgs[i]); @@ -739,6 +764,8 @@ static int drm_dp_i2c_xfer(struct i2c_adapter *adapter, struct i2c_msg *msgs, msg.size = 0; (void)drm_dp_i2c_do_msg(aux, &msg); + mutex_unlock(&aux->hw_mutex); + return err; } |