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 <[email protected]> Signed-off-by: David S. Miller <[email protected]>
k1132 · Aug 16, 2011 · a27fc96 · a27fc96
1 parent acf42a2
commit a27fc96
Showing 1 changed file with 6 additions and 0 deletions.
diff --git 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