rt2x00: Re-order tx descriptor writing code in drivers.
Where possible, write the tx descriptor words from start to end, to
follow a logical ordering of words.
Where this is not possible (in rt2400pci, rt2500pci and rt61pci) add
a comment as to why word 0 needs to be written last.
Signed-off-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2400pci.c b/drivers/net/wireless/rt2x00/rt2400pci.c
index 4b38451..1eff6ec 100644
--- a/drivers/net/wireless/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/rt2x00/rt2400pci.c
@@ -1039,6 +1039,11 @@
rt2x00_set_field32(&word, TXD_W3_PLCP_LENGTH_HIGH_BUSY, 1);
rt2x00_desc_write(txd, 4, word);
+ /*
+ * Writing TXD word 0 must the last to prevent a race condition with
+ * the device, whereby the device may take hold of the TXD before we
+ * finished updating it.
+ */
rt2x00_desc_read(txd, 0, &word);
rt2x00_set_field32(&word, TXD_W0_OWNER_NIC, 1);
rt2x00_set_field32(&word, TXD_W0_VALID, 1);