From 2231b16e0aec002cd955a64a9ccc795f3c402c00 Mon Sep 17 00:00:00 2001
From: whitequark <whitequark@whitequark.org>
Date: Wed, 30 Aug 2017 14:35:25 +0000
Subject: [PATCH] firmware: reduce ethmac maximum burst size by one.

Empirically, this much reduces packet loss. I'm not really sure why,
but it seems safe to do the change.
---
 artiq/firmware/runtime/ethmac.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/artiq/firmware/runtime/ethmac.rs b/artiq/firmware/runtime/ethmac.rs
index 23047bab0..c31e64ad7 100644
--- a/artiq/firmware/runtime/ethmac.rs
+++ b/artiq/firmware/runtime/ethmac.rs
@@ -26,7 +26,7 @@ impl Device for EthernetDevice {
     fn limits(&self) -> DeviceLimits {
         let mut limits = DeviceLimits::default();
         limits.max_transmission_unit = 1500;
-        limits.max_burst_size = Some(RX_BUFFERS.len());
+        limits.max_burst_size = Some(RX_BUFFERS.len() - 1);
         limits
     }