Hello,
I'm currently using the MV643xx Ethernet driver on my board. When I run the command :
# ifconfig eth0 down
I see the following message :
eth0: Error on Tx descriptor free - could not free 1 descriptors
I went through the code, and saw that this message is displayed in mv64340_eth_free_tx_rings(). This function frees all remaining skbs (registered in the mp->tx_skb array), and decrement mp->tx_ring_skbs. Then, it checks if it reached 0. In my case, it is still 1.
In fact, mp->tx_ring_skbs is initialized to 0 and then incremented in mv64340_eth_start_xmit() (when a transmission starts), and is decremented in mv64340_eth_free_tx_queue (when the transmission is done). But the decrementation only occurs if mp->tx_ring_skbs is different from one. I don't understand why.
At the end of mv64340_eth_free_tx_queue(), the following code makes sure that the number of skbs did not reach 0 :
if (mp->tx_ring_skbs == 0)
panic("ERROR - TX outstanding SKBs counter is corrupted");Well, my question is simply : why can't we decrement the mp->tx_ring_skbs counter to 0 ?
What needs to be fixed ? The decrementation of the counter, or the function that frees the TX queue when the interface is stopped ?
I've seen similar code in the Titan GE driver.
Do not hesitate to ask for further details,
Thanks,
Thomas -- PETAZZONI Thomas - thomas.petazzoni@xxxxxxxx http://thomas.enix.org - Jabber: kos_tom@xxxxxxxxxxxxx KOS: http://kos.enix.org/ - Lolut: http://lolut.utbm.info Fingerprint : 0BE1 4CF3 CEA4 AC9D CC6E 1624 F653 CB30 98D3 F7A7
