r8169 rx descriptors

["Denys Fedoryshchenko" <denys@visp.net.lb>]

>From NetBSD sources
http://cvsweb.netbsd.org/bsdweb.cgi/~checkout~/src/sys/dev/ic/rtl8169.c?rev=1.14.2.7&content-type=text/plain&logsort=rev&f=h&only_with_tag=netbsd-3

 *      o RX and TX DMA rings can have up to 1024 descriptors
 *        (the 8139C+ allows a maximum of 64)



Why in Linux source:

#define NUM_TX_DESC     64      /* Number of Tx descriptor registers */
#define NUM_RX_DESC     256     /* Number of Rx descriptor registers */

Is it possible to do them changeable over ethtool -g ?
Maybe NetBSD developers signed NDA and have access to datasheets?

Also i seen in one patch from Realtek , something similar to
-#define RX_DMA_BURST    6       /* Maximum PCI burst, '6' is 1024 */
+#define RX_DMA_BURST    7       /* Maximum PCI burst, '6' is 1024 */

Why it is reverted or not applied?


In sources from Realtek website it is 
#define RX_DMA_BURST	7	/* Maximum PCI burst, '7' is unlimited */
#define TX_DMA_BURST	7	/* Maximum PCI burst, '7' is unlimited */

I will try to change burst settings on my router, and waiting comments about 

--
Denys Fedoryshchenko
Technical Manager
Virtual ISP S.A.L.