p54: disable channels with incomplete calibration data sets

James Grossmann [1] reported that p54 spews out confusing
messages instead of preventing the mayhem from happening.

the reason is that "p54: generate channel list dynamically"
is not perfect. It didn't discard incomplete channel data
sets and therefore p54 advertised to support them as well.

[1]: http://marc.info/?l=linux-wireless&m=125699830215890

Cc: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: James Grossmann <cctsurf@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@web.de>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 19 insertions, 12 deletions

diff --git a/drivers/net/wireless/p54/eeprom.c b/drivers/net/wireless/p54/eeprom.c
index 0efe67deedee..8e3818f6832e 100644
--- a/drivers/net/wireless/p54/eeprom.c
+++ b/drivers/net/wireless/p54/eeprom.c
@@ -126,7 +126,7 @@ static int p54_generate_band(struct ieee80211_hw *dev,
         int ret = -ENOMEM;
 
         if ((!list->entries) || (!list->band_channel_num[band]))
-                return 0;
+                return -EINVAL;
 
         tmp = kzalloc(sizeof(*tmp), GFP_KERNEL);
         if (!tmp)
@@ -158,6 +158,7 @@ static int p54_generate_band(struct ieee80211_hw *dev,
                                (list->channels[i].data & CHAN_HAS_CURVE ? "" :
                                 " [curve data]"),
                                list->channels[i].index, list->channels[i].freq);
+                        continue;
                 }
 
                 tmp->channels[j].band = list->channels[i].band;
@@ -165,7 +166,16 @@ static int p54_generate_band(struct ieee80211_hw *dev,
                 j++;
         }
 
-        tmp->n_channels = list->band_channel_num[band];
+        if (j == 0) {
+                printk(KERN_ERR "%s: Disabling totally damaged %s band.\n",
+                       wiphy_name(dev->wiphy), (band == IEEE80211_BAND_2GHZ) ?
+                       "2 GHz" : "5 GHz");
+
+                ret = -ENODATA;
+                goto err_out;
+        }
+
+        tmp->n_channels = j;
         old = priv->band_table[band];
         priv->band_table[band] = tmp;
         if (old) {
@@ -228,13 +238,13 @@ static int p54_generate_channel_lists(struct ieee80211_hw *dev)
         struct p54_common *priv = dev->priv;
         struct p54_channel_list *list;
         unsigned int i, j, max_channel_num;
-        int ret = -ENOMEM;
+        int ret = 0;
         u16 freq;
 
         if ((priv->iq_autocal_len != priv->curve_data->entries) ||
             (priv->iq_autocal_len != priv->output_limit->entries))
-                printk(KERN_ERR "%s: EEPROM is damaged... you may not be able"
-                                "to use all channels with this device.\n",
+                printk(KERN_ERR "%s: Unsupported or damaged EEPROM detected. "
+                                "You may not be able to use all channels.\n",
                                 wiphy_name(dev->wiphy));
 
         max_channel_num = max_t(unsigned int, priv->output_limit->entries,
@@ -243,8 +253,10 @@ static int p54_generate_channel_lists(struct ieee80211_hw *dev)
                                 priv->curve_data->entries);
 
         list = kzalloc(sizeof(*list), GFP_KERNEL);
-        if (!list)
+        if (!list) {
+                ret = -ENOMEM;
                 goto free;
+        }
 
         list->max_entries = max_channel_num;
         list->channels = kzalloc(sizeof(struct p54_channel_entry) *
@@ -282,13 +294,8 @@ static int p54_generate_channel_lists(struct ieee80211_hw *dev)
              p54_compare_channels, NULL);
 
         for (i = 0, j = 0; i < IEEE80211_NUM_BANDS; i++) {
-                if (list->band_channel_num[i]) {
-                        ret = p54_generate_band(dev, list, i);
-                        if (ret)
-                                goto free;
-
+                if (p54_generate_band(dev, list, i) == 0)
                         j++;
-                }
         }
         if (j == 0) {
                 /* no useable band available. */