unsigned int offset, void *buffer, size_t size)
{
struct drm_dp_aux_msg msg;
- unsigned int retry;
- int err = 0;
+ unsigned int retry, native_reply;
+ int err = 0, ret = 0;
memset(&msg, 0, sizeof(msg));
msg.address = offset;
* sufficient, bump to 32 which makes Dell 4k monitors happier.
*/
for (retry = 0; retry < 32; retry++) {
-
- err = aux->transfer(aux, &msg);
- if (err < 0) {
- if (err == -EBUSY)
- continue;
-
- goto unlock;
+ 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)
- err = -EPROTO;
- goto unlock;
-
- case DP_AUX_NATIVE_REPLY_NACK:
- err = -EIO;
- goto unlock;
+ 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_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");
- err = -EIO;
+ ret = err;
unlock:
mutex_unlock(&aux->hw_mutex);
- return err;
+ return ret;
}
/**
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);
}
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]);
msg.size = 0;
(void)drm_dp_i2c_do_msg(aux, &msg);
- mutex_unlock(&aux->hw_mutex);
-
return err;
}
.master_xfer = drm_dp_i2c_xfer,
};
+static struct drm_dp_aux *i2c_to_aux(struct i2c_adapter *i2c)
+{
+ return container_of(i2c, struct drm_dp_aux, ddc);
+}
+
+static void lock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+ mutex_lock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
+static int trylock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+ return mutex_trylock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
+static void unlock_bus(struct i2c_adapter *i2c, unsigned int flags)
+{
+ mutex_unlock(&i2c_to_aux(i2c)->hw_mutex);
+}
+
/**
- * drm_dp_aux_register() - initialise and register aux channel
+ * drm_dp_aux_init() - minimally initialise an aux channel
* @aux: DisplayPort AUX channel
*
- * Returns 0 on success or a negative error code on failure.
+ * If you need to use the drm_dp_aux's i2c adapter prior to registering it
+ * with the outside world, call drm_dp_aux_init() first. You must still
+ * call drm_dp_aux_register() once the connector has been registered to
+ * allow userspace access to the auxiliary DP channel.
*/
-int drm_dp_aux_register(struct drm_dp_aux *aux)
+void drm_dp_aux_init(struct drm_dp_aux *aux)
{
- int ret;
-
mutex_init(&aux->hw_mutex);
aux->ddc.algo = &drm_dp_i2c_algo;
aux->ddc.algo_data = aux;
aux->ddc.retries = 3;
+ aux->ddc.lock_bus = lock_bus;
+ aux->ddc.trylock_bus = trylock_bus;
+ aux->ddc.unlock_bus = unlock_bus;
+}
+EXPORT_SYMBOL(drm_dp_aux_init);
+
+/**
+ * drm_dp_aux_register() - initialise and register aux channel
+ * @aux: DisplayPort AUX channel
+ *
+ * Automatically calls drm_dp_aux_init() if this hasn't been done yet.
+ *
+ * Returns 0 on success or a negative error code on failure.
+ */
+int drm_dp_aux_register(struct drm_dp_aux *aux)
+{
+ int ret;
+
+ if (!aux->ddc.algo)
+ drm_dp_aux_init(aux);
+
aux->ddc.class = I2C_CLASS_DDC;
aux->ddc.owner = THIS_MODULE;
aux->ddc.dev.parent = aux->dev;
projects / deliverable / linux.git / blobdiff