[PATCH 2.5] : ir251_qos_param-2.diff

From: Jean Tourrilhes (jt@bougret.hpl.hp.com)
Date: Thu Oct 10 2002 - 19:17:10 EST


ir251_qos_param-2.diff :
----------------------
        o [FEATURE] Fix some comments
        o [FEATURE] printk warning when we detect buggy QoS from peer
        o [CORRECT] Workaround NULL QoS bitfields
        o [CORRECT] Workaround oversized QoS bitfields
        o [FEATURE] Add sysctl "max_tx_window" to limit IrLAP Tx Window

diff -u -p linux/net/irda/qos.d3.c linux/net/irda/qos.c
--- linux/net/irda/qos.d3.c Thu Oct 10 14:54:58 2002
+++ linux/net/irda/qos.c Thu Oct 10 15:11:27 2002
@@ -70,13 +70,18 @@ unsigned sysctl_min_tx_turn_time = 10;
  * 1.2, chapt 5.3.2.1, p41). But, this number includes the LAP header
  * (2 bytes), and CRC (32 bits at 4 Mb/s). So, for the I field (LAP
  * payload), that's only 2042 bytes. Oups !
- * I've had trouble trouble transmitting 2048 bytes frames with USB
- * dongles and nsc-ircc at 4 Mb/s, so adjust to 2042... I don't know
- * if this bug applies only for 2048 bytes frames or all negociated
- * frame sizes, but all hardware seem to support "2048 bytes" frames.
- * You can use the sysctl to play with this value anyway.
+ * My nsc-ircc hardware has troubles receiving 2048 bytes frames at 4 Mb/s,
+ * so adjust to 2042... I don't know if this bug applies only for 2048
+ * bytes frames or all negociated frame sizes, but you can use the sysctl
+ * to play with this value anyway.
  * Jean II */
 unsigned sysctl_max_tx_data_size = 2042;
+/*
+ * Maximum transmit window, i.e. number of LAP frames between turn-around.
+ * This allow to override what the peer told us. Some peers are buggy and
+ * don't always support what they tell us.
+ * Jean II */
+unsigned sysctl_max_tx_window = 7;
 
 static int irlap_param_baud_rate(void *instance, irda_param_t *param, int get);
 static int irlap_param_link_disconnect(void *instance, irda_param_t *parm,
@@ -184,7 +189,19 @@ int msb_index (__u16 word)
 {
         __u16 msb = 0x8000;
         int index = 15; /* Current MSB */
-
+
+ /* Check for buggy peers.
+ * Note : there is a small probability that it could be us, but I
+ * would expect driver authors to catch that pretty early and be
+ * able to check precisely what's going on. If a end user sees this,
+ * it's very likely the peer. - Jean II */
+ if (word == 0) {
+ WARNING("%s(), Detected buggy peer, adjust null PV to 0x1!\n",
+ __FUNCTION__);
+ /* The only safe choice (we don't know the array size) */
+ word = 0x1;
+ }
+
         while (msb) {
                 if (word & msb)
                         break; /* Found it! */
@@ -335,10 +352,14 @@ void irlap_adjust_qos_settings(struct qo
 
         /*
          * Make sure the mintt is sensible.
+ * Main culprit : Ericsson T39. - Jean II
          */
         if (sysctl_min_tx_turn_time > qos->min_turn_time.value) {
                 int i;
 
+ WARNING("%s(), Detected buggy peer, adjust mtt to %dus!\n",
+ __FUNCTION__, sysctl_min_tx_turn_time);
+
                 /* We don't really need bits, but easier this way */
                 i = value_highest_bit(sysctl_min_tx_turn_time, min_turn_times,
                                       8, &qos->min_turn_time.bits);
@@ -398,6 +419,11 @@ void irlap_adjust_qos_settings(struct qo
         if (qos->data_size.value > sysctl_max_tx_data_size)
                 /* Allow non discrete adjustement to avoid loosing capacity */
                 qos->data_size.value = sysctl_max_tx_data_size;
+ /*
+ * Override Tx window if user request it. - Jean II
+ */
+ if (qos->window_size.value > sysctl_max_tx_window)
+ qos->window_size.value = sysctl_max_tx_window;
 }
 
 /*
diff -u -p linux/net/irda/irsysctl.d3.c linux/net/irda/irsysctl.c
--- linux/net/irda/irsysctl.d3.c Thu Oct 10 14:55:26 2002
+++ linux/net/irda/irsysctl.c Thu Oct 10 15:11:27 2002
@@ -35,7 +35,7 @@
 #define NET_IRDA 412 /* Random number */
 enum { DISCOVERY=1, DEVNAME, DEBUG, FAST_POLL, DISCOVERY_SLOTS,
        DISCOVERY_TIMEOUT, SLOT_TIMEOUT, MAX_BAUD_RATE, MIN_TX_TURN_TIME,
- MAX_TX_DATA_SIZE, MAX_NOREPLY_TIME, WARN_NOREPLY_TIME,
+ MAX_TX_DATA_SIZE, MAX_TX_WINDOW, MAX_NOREPLY_TIME, WARN_NOREPLY_TIME,
        LAP_KEEPALIVE_TIME };
 
 extern int sysctl_discovery;
@@ -48,6 +48,7 @@ extern char sysctl_devname[];
 extern int sysctl_max_baud_rate;
 extern int sysctl_min_tx_turn_time;
 extern int sysctl_max_tx_data_size;
+extern int sysctl_max_tx_window;
 extern int sysctl_max_noreply_time;
 extern int sysctl_warn_noreply_time;
 extern int sysctl_lap_keepalive_time;
@@ -69,6 +70,8 @@ static int max_min_tx_turn_time = 10000;
 static int min_min_tx_turn_time = 0;
 static int max_max_tx_data_size = 2048; /* See qos.c - IrLAP spec */
 static int min_max_tx_data_size = 64;
+static int max_max_tx_window = 7; /* See qos.c - IrLAP spec */
+static int min_max_tx_window = 1;
 static int max_max_noreply_time = 40; /* See qos.c - IrLAP spec */
 static int min_max_noreply_time = 3;
 static int max_warn_noreply_time = 3; /* 3s == standard */
@@ -125,6 +128,9 @@ static ctl_table irda_table[] = {
         { MAX_TX_DATA_SIZE, "max_tx_data_size", &sysctl_max_tx_data_size,
           sizeof(int), 0644, NULL, &proc_dointvec_minmax, &sysctl_intvec,
           NULL, &min_max_tx_data_size, &max_max_tx_data_size },
+ { MAX_TX_WINDOW, "max_tx_window", &sysctl_max_tx_window,
+ sizeof(int), 0644, NULL, &proc_dointvec_minmax, &sysctl_intvec,
+ NULL, &min_max_tx_window, &max_max_tx_window },
         { MAX_NOREPLY_TIME, "max_noreply_time", &sysctl_max_noreply_time,
           sizeof(int), 0644, NULL, &proc_dointvec_minmax, &sysctl_intvec,
           NULL, &min_max_noreply_time, &max_max_noreply_time },
diff -u -p linux/net/irda/parameters.d3.c linux/net/irda/parameters.c
--- linux/net/irda/parameters.d3.c Thu Oct 10 14:55:59 2002
+++ linux/net/irda/parameters.c Thu Oct 10 15:14:30 2002
@@ -200,11 +200,13 @@ static int irda_extract_integer(void *se
 {
         irda_param_t p;
         int n = 0;
+ int extract_len; /* Real lenght we extract */
         int err;
 
         p.pi = pi; /* In case handler needs to know */
         p.pl = buf[1]; /* Extract lenght of value */
         p.pv.i = 0; /* Clear value */
+ extract_len = p.pl; /* Default : extract all */
 
         /* Check if buffer is long enough for parsing */
         if (len < (2+p.pl)) {
@@ -217,18 +219,30 @@ static int irda_extract_integer(void *se
         /*
          * Check that the integer length is what we expect it to be. If the
          * handler want a 16 bits integer then a 32 bits is not good enough
+ * PV_INTEGER means that the handler is flexible.
          */
         if (((type & PV_MASK) != PV_INTEGER) && ((type & PV_MASK) != p.pl)) {
                 ERROR("%s: invalid parameter length! "
                       "Expected %d bytes, but value had %d bytes!\n",
                       __FUNCTION__, type & PV_MASK, p.pl);
 
- /* Skip parameter */
- return p.pl+2;
+ /* Most parameters are bit/byte fields or little endian,
+ * so it's ok to only extract a subset of it (the subset
+ * that the handler expect). This is necessary, as some
+ * broken implementations seems to add extra undefined bits.
+ * If the parameter is shorter than we expect or is big
+ * endian, we can't play those tricks. Jean II */
+ if((p.pl < (type & PV_MASK)) || (type & PV_BIG_ENDIAN)) {
+ /* Skip parameter */
+ return p.pl+2;
+ } else {
+ /* Extract subset of it, fallthrough */
+ extract_len = type & PV_MASK;
+ }
         }
 
 
- switch (p.pl) {
+ switch (extract_len) {
         case 1:
                 n += irda_param_unpack(buf+2, "b", &p.pv.i);
                 break;
-
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