From e6136eb07580195a5c292699a718fb525e9e0f5b Mon Sep 17 00:00:00 2001
From: Gav Wood <gavin@ethcore.io>
Date: Thu, 24 Mar 2016 14:13:43 +0000
Subject: [PATCH] Fix mining.

---
 rpc/src/v1/impls/eth.rs | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/rpc/src/v1/impls/eth.rs b/rpc/src/v1/impls/eth.rs
index 638403c7d..a59c68ec6 100644
--- a/rpc/src/v1/impls/eth.rs
+++ b/rpc/src/v1/impls/eth.rs
@@ -197,6 +197,8 @@ impl<C, S, A, M, EM> EthClient<C, S, A, M, EM>
 	}
 }
 
+const MAX_QUEUE_SIZE_TO_MINE_ON: usize = 4;	// because uncles go back 6.
+
 impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 	where C: BlockChainClient + 'static,
 		  S: SyncProvider + 'static,
@@ -401,7 +403,7 @@ impl<C, S, A, M, EM> Eth for EthClient<C, S, A, M, EM>
 				// check if we're still syncing and return empty strings in that case
 				{
 					let sync = take_weak!(self.sync);
-					if sync.status().state != SyncState::Idle && client.queue_info().is_empty() {
+					if sync.status().state != SyncState::Idle && !client.queue_info().total_queue_size() > MAX_QUEUE_SIZE_TO_MINE_ON {
 						trace!(target: "miner", "Syncing. Cannot give any work.");
 						return to_value(&(String::new(), String::new(), String::new()));
 					}