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- /*
- * wireless_qual_to_percent
- *
- * Convert an iw_quality structure from SIOCGIWSTATS into a magical signal
- * strength percentage.
- *
- */
- static int
- wireless_qual_to_percent (const struct iw_quality *qual,
- const struct iw_quality *max_qual)
- {
- int percent = -1;
- int level_percent = -1;
- g_return_val_if_fail (qual != NULL, -1);
- g_return_val_if_fail (max_qual != NULL, -1);
- nm_log_dbg (LOGD_WIFI,
- "QL: qual %d/%u/0x%X, level %d/%u/0x%X, noise %d/%u/0x%X, updated: 0x%X ** MAX: qual %d/%u/0x%X, level %d/%u/0x%X, noise %d/%u/0x%X, updated: 0x%X",
- (__s8) qual->qual, qual->qual, qual->qual,
- (__s8) qual->level, qual->level, qual->level,
- (__s8) qual->noise, qual->noise, qual->noise,
- qual->updated,
- (__s8) max_qual->qual, max_qual->qual, max_qual->qual,
- (__s8) max_qual->level, max_qual->level, max_qual->level,
- (__s8) max_qual->noise, max_qual->noise, max_qual->noise,
- max_qual->updated);
- /* Try using the card's idea of the signal quality first as long as it tells us what the max quality is.
- * Drivers that fill in quality values MUST treat them as percentages, ie the "Link Quality" MUST be
- * bounded by 0 and max_qual->qual, and MUST change in a linear fashion. Within those bounds, drivers
- * are free to use whatever they want to calculate "Link Quality".
- */
- if ((max_qual->qual != 0) && !(max_qual->updated & IW_QUAL_QUAL_INVALID) && !(qual->updated & IW_QUAL_QUAL_INVALID))
- percent = (int)(100 * ((double)qual->qual / (double)max_qual->qual));
- /* If the driver doesn't specify a complete and valid quality, we have two options:
- *
- * 1) dBm: driver must specify max_qual->level = 0, and have valid values for
- * qual->level and (qual->noise OR max_qual->noise)
- * 2) raw RSSI: driver must specify max_qual->level > 0, and have valid values for
- * qual->level and max_qual->level
- *
- * This is the WEXT spec. If this interpretation is wrong, I'll fix it. Otherwise,
- * If drivers don't conform to it, they are wrong and need to be fixed.
- */
- if ( (max_qual->level == 0) && !(max_qual->updated & IW_QUAL_LEVEL_INVALID) /* Valid max_qual->level == 0 */
- && !(qual->updated & IW_QUAL_LEVEL_INVALID) /* Must have valid qual->level */
- && ( ((max_qual->noise > 0) && !(max_qual->updated & IW_QUAL_NOISE_INVALID)) /* Must have valid max_qual->noise */
- || ((qual->noise > 0) && !(qual->updated & IW_QUAL_NOISE_INVALID))) /* OR valid qual->noise */
- ) {
- /* Absolute power values (dBm) */
- /* Reasonable fallbacks for dumb drivers that don't specify either level. */
- #define FALLBACK_NOISE_FLOOR_DBM -90
- #define FALLBACK_SIGNAL_MAX_DBM -20
- int max_level = FALLBACK_SIGNAL_MAX_DBM;
- int noise = FALLBACK_NOISE_FLOOR_DBM;
- int level = qual->level - 0x100;
- level = CLAMP (level, FALLBACK_NOISE_FLOOR_DBM, FALLBACK_SIGNAL_MAX_DBM);
- if ((qual->noise > 0) && !(qual->updated & IW_QUAL_NOISE_INVALID))
- noise = qual->noise - 0x100;
- else if ((max_qual->noise > 0) && !(max_qual->updated & IW_QUAL_NOISE_INVALID))
- noise = max_qual->noise - 0x100;
- noise = CLAMP (noise, FALLBACK_NOISE_FLOOR_DBM, FALLBACK_SIGNAL_MAX_DBM);
- /* A sort of signal-to-noise ratio calculation */
- level_percent = (int)(100 - 70 *(
- ((double)max_level - (double)level) /
- ((double)max_level - (double)noise)));
- nm_log_dbg (LOGD_WIFI, "QL1: level_percent is %d. max_level %d, level %d, noise_floor %d.",
- level_percent, max_level, level, noise);
- } else if ( (max_qual->level != 0)
- && !(max_qual->updated & IW_QUAL_LEVEL_INVALID) /* Valid max_qual->level as upper bound */
- && !(qual->updated & IW_QUAL_LEVEL_INVALID)) {
- /* Relative power values (RSSI) */
- int level = qual->level;
- /* Signal level is relavtive (0 -> max_qual->level) */
- level = CLAMP (level, 0, max_qual->level);
- level_percent = (int)(100 * ((double)level / (double)max_qual->level));
- nm_log_dbg (LOGD_WIFI, "QL2: level_percent is %d. max_level %d, level %d.",
- level_percent, max_qual->level, level);
- } else if (percent == -1) {
- nm_log_dbg (LOGD_WIFI, "QL: Could not get quality %% value from driver. Driver is probably buggy.");
- }
- /* If the quality percent was 0 or doesn't exist, then try to use signal levels instead */
- if ((percent < 1) && (level_percent >= 0))
- percent = level_percent;
- nm_log_dbg (LOGD_WIFI, "QL: Final quality percent is %d (%d).",
- percent, CLAMP (percent, 0, 100));
- return (CLAMP (percent, 0, 100));
- }
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