From a27fc96b0317b732b68b5f781bbdeb56ab5082a8 Mon Sep 17 00:00:00 2001 From: Ben Hutchings Date: Mon, 15 Aug 2011 14:09:22 +0000 Subject: [PATCH] ethtool: Note common alternate exit condition for interrupt coalescing Many implementations ignore the value of max_frames and do not treat usecs == 0 as special. Document this as deprecated. Signed-off-by: Ben Hutchings Signed-off-by: David S. Miller --- include/linux/ethtool.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index 42378b34ae8f..3829712ccc05 100644 --- a/include/linux/ethtool.h +++ b/include/linux/ethtool.h @@ -173,6 +173,12 @@ struct ethtool_eeprom { * would cause interrupts to never be generated. To disable * coalescing, set usecs = 0 and max_frames = 1. * + * Some implementations ignore the value of max_frames and use the + * condition: + * time_since_first_completion >= usecs + * This is deprecated. Drivers for hardware that does not support + * counting completions should validate that max_frames == !rx_usecs. + * * Adaptive RX/TX coalescing is an algorithm implemented by some * drivers to improve latency under low packet rates and improve * throughput under high packet rates. Some drivers only implement -- 2.30.2