Re: Commit 741b4fbc44 (mac80211: fix TX sequence numbers) breaks rtl8187

[Larry Finger <Larry.Finger@lwfinger.net>]

Johannes Berg wrote:
> On Wed, 2008-07-23 at 00:43 -0500, Larry Finger wrote:
>> Johannes,
>>
>> In the current wireless-testing (v2.6.26-rc9-14207-ga520bdb), rtl8187 is broken. 
>> In most cases, it is unable to complete a connection. Occasionally, it will 
>> authenticate and even get an IP using DHCP; however, only a few pings get 
>> through to the AP before the connection fails completely.
>>
>> Using bisection, this problem was traced to:
>>
>> ==================================================
>> commit 741b4fbc441dba885cc8f97a10e87f2acd04c5f2
>> Author: Johannes Berg <johannes@sipsolutions.net>
>> Date:   Thu Jul 10 11:21:26 2008 +0200
>>
>>      mac80211: fix TX sequence numbers
> 
>> The validity of the bisection was confirmed by reverse application of the patch. 
>> The resulting driver worked.
>>
>> The appears that rtl8187 needs some kind of modification such as b43, b43legacy, 
>> and rt2x00 got in the original patch. I'll be studying the changes to the other 
>> drivers to see if I can find the problem, but I will appreciate your help when 
>> you get a chance. Perhaps after your trip to Canada is over.
> 
> Oh, crap. If you look at the patch, it removes the sequence numbers for
> non-TID frames, and puts them back into rt2x00 because I thought rt2x00
> was the only driver that needed software sequence numbering. It looks
> like rtl8187 and zd1211 might need that too, so we need to copy the
> rt2x00 code that I put into that particular patch to those drivers.

I tried something like that, but it didn't work. Maybe you can see what is wrong 
here:


Index: wireless-testing/drivers/net/wireless/rtl8187.h
===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtl8187.h
+++ wireless-testing/drivers/net/wireless/rtl8187.h
@@ -100,6 +100,7 @@ struct rtl8187_priv {
  	struct usb_device *udev;
  	u32 rx_conf;
  	u16 txpwr_base;
+	u16 seqno;
  	u8 asic_rev;
  	u8 is_rtl8187b;
  	enum {
Index: wireless-testing/drivers/net/wireless/rtl8187_dev.c
===================================================================
--- wireless-testing.orig/drivers/net/wireless/rtl8187_dev.c
+++ wireless-testing/drivers/net/wireless/rtl8187_dev.c
@@ -169,6 +169,7 @@ static int rtl8187_tx(struct ieee80211_h
  {
  	struct rtl8187_priv *priv = dev->priv;
  	struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+	struct ieee80211_hdr *ieee80211hdr = (struct ieee80211_hdr *)skb->data;
  	unsigned int ep;
  	void *buf;
  	struct urb *urb;
@@ -198,6 +199,14 @@ static int rtl8187_tx(struct ieee80211_h
  		flags |= ieee80211_get_rts_cts_rate(dev, info)->hw_value << 19;
  	}

+	/* XXX: This sequence is an attempt to match what happens in r2x00. */
+	if (info->flags & IEEE80211_TX_CTL_ASSIGN_SEQ) {
+		if (info->flags & IEEE80211_TX_CTL_FIRST_FRAGMENT)
+			priv->seqno += 0x10;
+		ieee80211hdr->seq_ctrl &= cpu_to_le16(IEEE80211_SCTL_FRAG);
+		ieee80211hdr->seq_ctrl |= cpu_to_le16(priv->seqno);
+	}
+
  	if (!priv->is_rtl8187b) {
  		struct rtl8187_tx_hdr *hdr =
  			(struct rtl8187_tx_hdr *)skb_push(skb, sizeof(*hdr));