__le16 channel; /* channel number */
__le16 non_cfg_phy[RX_RES_PHY_CNT]; /* upto 14 phy entries */
__le32 reserved2;
- __le32 rate_n_flags;
- __le16 byte_count; /* frame's byte-count */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+ __le16 byte_count; /* frame's byte-count */
__le16 reserved3;
} __attribute__ ((packed));
* (5)
* Tx Commands & Responses:
*
+ * Driver must place each REPLY_TX command into one of the prioritized Tx
+ * queues in host DRAM, shared between driver and device (see comments for
+ * SCD registers and Tx/Rx Queues). When the device's Tx scheduler and uCode
+ * are preparing to transmit, the device pulls the Tx command over the PCI
+ * bus via one of the device's Tx DMA channels, to fill an internal FIFO
+ * from which data will be transmitted.
+ *
+ * uCode handles all timing and protocol related to control frames
+ * (RTS/CTS/ACK), based on flags in the Tx command. uCode and Tx scheduler
+ * handle reception of block-acks; uCode updates the host driver via
+ * REPLY_COMPRESSED_BA (4965).
+ *
+ * uCode handles retrying Tx when an ACK is expected but not received.
+ * This includes trying lower data rates than the one requested in the Tx
+ * command, as set up by the REPLY_RATE_SCALE (for 3945) or
+ * REPLY_TX_LINK_QUALITY_CMD (4965).
+ *
+ * Driver sets up transmit power for various rates via REPLY_TX_PWR_TABLE_CMD.
+ * This command must be executed after every RXON command, before Tx can occur.
*****************************************************************************/
-/* Tx flags */
+/* REPLY_TX Tx flags field */
+
+/* 1: Use Request-To-Send protocol before this frame.
+ * Mutually exclusive vs. TX_CMD_FLG_CTS_MSK. */
#define TX_CMD_FLG_RTS_MSK __constant_cpu_to_le32(1 << 1)
+
+/* 1: Transmit Clear-To-Send to self before this frame.
+ * Driver should set this for AUTH/DEAUTH/ASSOC-REQ/REASSOC mgmnt frames.
+ * Mutually exclusive vs. TX_CMD_FLG_RTS_MSK. */
#define TX_CMD_FLG_CTS_MSK __constant_cpu_to_le32(1 << 2)
+
+/* 1: Expect ACK from receiving station
+ * 0: Don't expect ACK (MAC header's duration field s/b 0)
+ * Set this for unicast frames, but not broadcast/multicast. */
#define TX_CMD_FLG_ACK_MSK __constant_cpu_to_le32(1 << 3)
+
+/* For 4965:
+ * 1: Use rate scale table (see REPLY_TX_LINK_QUALITY_CMD).
+ * Tx command's initial_rate_index indicates first rate to try;
+ * uCode walks through table for additional Tx attempts.
+ * 0: Use Tx rate/MCS from Tx command's rate_n_flags field.
+ * This rate will be used for all Tx attempts; it will not be scaled. */
#define TX_CMD_FLG_STA_RATE_MSK __constant_cpu_to_le32(1 << 4)
+
+/* 1: Expect immediate block-ack.
+ * Set when Txing a block-ack request frame. Also set TX_CMD_FLG_ACK_MSK. */
#define TX_CMD_FLG_IMM_BA_RSP_MASK __constant_cpu_to_le32(1 << 6)
+
+/* 1: Frame requires full Tx-Op protection.
+ * Set this if either RTS or CTS Tx Flag gets set. */
#define TX_CMD_FLG_FULL_TXOP_PROT_MSK __constant_cpu_to_le32(1 << 7)
+
+/* Tx antenna selection field; used only for 3945, reserved (0) for 4965.
+ * Set field to "0" to allow 3945 uCode to select antenna (normal usage). */
#define TX_CMD_FLG_ANT_SEL_MSK __constant_cpu_to_le32(0xf00)
#define TX_CMD_FLG_ANT_A_MSK __constant_cpu_to_le32(1 << 8)
#define TX_CMD_FLG_ANT_B_MSK __constant_cpu_to_le32(1 << 9)
-/* ucode ignores BT priority for this frame */
+/* 1: Ignore Bluetooth priority for this frame.
+ * 0: Delay Tx until Bluetooth device is done (normal usage). */
#define TX_CMD_FLG_BT_DIS_MSK __constant_cpu_to_le32(1 << 12)
-/* ucode overrides sequence control */
+/* 1: uCode overrides sequence control field in MAC header.
+ * 0: Driver provides sequence control field in MAC header.
+ * Set this for management frames, non-QOS data frames, non-unicast frames,
+ * and also in Tx command embedded in REPLY_SCAN_CMD for active scans. */
#define TX_CMD_FLG_SEQ_CTL_MSK __constant_cpu_to_le32(1 << 13)
-/* signal that this frame is non-last MPDU */
+/* 1: This frame is non-last MPDU; more fragments are coming.
+ * 0: Last fragment, or not using fragmentation. */
#define TX_CMD_FLG_MORE_FRAG_MSK __constant_cpu_to_le32(1 << 14)
-/* calculate TSF in outgoing frame */
+/* 1: uCode calculates and inserts Timestamp Function (TSF) in outgoing frame.
+ * 0: No TSF required in outgoing frame.
+ * Set this for transmitting beacons and probe responses. */
#define TX_CMD_FLG_TSF_MSK __constant_cpu_to_le32(1 << 16)
-/* activate TX calibration. */
-#define TX_CMD_FLG_CALIB_MSK __constant_cpu_to_le32(1 << 17)
-
-/* signals that 2 bytes pad was inserted
- after the MAC header */
+/* 1: Driver inserted 2 bytes pad after the MAC header, for (required) dword
+ * alignment of frame's payload data field.
+ * 0: No pad
+ * Set this for MAC headers with 26 or 30 bytes, i.e. those with QOS or ADDR4
+ * field (but not both). Driver must align frame data (i.e. data following
+ * MAC header) to DWORD boundary. */
#define TX_CMD_FLG_MH_PAD_MSK __constant_cpu_to_le32(1 << 20)
/* HCCA-AP - disable duration overwriting. */
#define TX_CMD_FLG_DUR_MSK __constant_cpu_to_le32(1 << 25)
+
/*
* TX command security control
*/
#define TX_CMD_SEC_KEY128 0x08
/*
- * TX command Frame life time
+ * 4965 uCode updates these Tx attempt count values in host DRAM.
+ * Used for managing Tx retries when expecting block-acks.
+ * Driver should set these fields to 0.
*/
-
struct iwl4965_dram_scratch {
- u8 try_cnt;
- u8 bt_kill_cnt;
+ u8 try_cnt; /* Tx attempts */
+ u8 bt_kill_cnt; /* Tx attempts blocked by Bluetooth device */
__le16 reserved;
} __attribute__ ((packed));
* REPLY_TX = 0x1c (command)
*/
struct iwl4965_tx_cmd {
+ /*
+ * MPDU byte count:
+ * MAC header (24/26/30/32 bytes) + 2 bytes pad if 26/30 header size,
+ * + 8 byte IV for CCM or TKIP (not used for WEP)
+ * + Data payload
+ * + 8-byte MIC (not used for CCM/WEP)
+ * NOTE: Does not include Tx command bytes, post-MAC pad bytes,
+ * MIC (CCM) 8 bytes, ICV (WEP/TKIP/CKIP) 4 bytes, CRC 4 bytes.i
+ * Range: 14-2342 bytes.
+ */
__le16 len;
+
+ /*
+ * MPDU or MSDU byte count for next frame.
+ * Used for fragmentation and bursting, but not 11n aggregation.
+ * Same as "len", but for next frame. Set to 0 if not applicable.
+ */
__le16 next_frame_len;
- __le32 tx_flags;
+
+ __le32 tx_flags; /* TX_CMD_FLG_* */
+
+ /* 4965's uCode may modify this field of the Tx command (in host DRAM!).
+ * Driver must also set dram_lsb_ptr and dram_msb_ptr in this cmd. */
struct iwl4965_dram_scratch scratch;
- __le32 rate_n_flags;
+
+ /* Rate for *all* Tx attempts, if TX_CMD_FLG_STA_RATE_MSK is cleared. */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+
+ /* Index of destination station in uCode's station table */
u8 sta_id;
- u8 sec_ctl;
+
+ /* Type of security encryption: CCM or TKIP */
+ u8 sec_ctl; /* TX_CMD_SEC_* */
+
+ /*
+ * Index into rate table (see REPLY_TX_LINK_QUALITY_CMD) for initial
+ * Tx attempt, if TX_CMD_FLG_STA_RATE_MSK is set. Normally "0" for
+ * data frames, this field may be used to selectively reduce initial
+ * rate (via non-0 value) for special frames (e.g. management), while
+ * still supporting rate scaling for all frames.
+ */
u8 initial_rate_index;
u8 reserved;
u8 key[16];
__le32 life_time;
__le32 attempt;
} stop_time;
+
+ /* Host DRAM physical address pointer to "scratch" in this command.
+ * Must be dword aligned. "0" in dram_lsb_ptr disables usage. */
__le32 dram_lsb_ptr;
u8 dram_msb_ptr;
+
u8 rts_retry_limit; /*byte 50 */
u8 data_retry_limit; /*byte 51 */
u8 tid_tspec;
__le16 pm_frame_timeout;
__le16 attempt_duration;
} timeout;
+
+ /*
+ * Duration of EDCA burst Tx Opportunity, in 32-usec units.
+ * Set this if txop time is not specified by HCCA protocol (e.g. by AP).
+ */
__le16 driver_txop;
+
+ /*
+ * MAC header goes here, followed by 2 bytes padding if MAC header
+ * length is 26 or 30 bytes, followed by payload data
+ */
u8 payload[0];
struct ieee80211_hdr hdr[0];
} __attribute__ ((packed));
};
/* *******************************
- * TX aggregation state
+ * TX aggregation status
******************************* */
enum {
AGG_TX_STATE_LAST_SENT_TRY_CNT_MSK | \
AGG_TX_STATE_LAST_SENT_BT_KILL_MSK)
+/* # tx attempts for first frame in aggregation */
#define AGG_TX_STATE_TRY_CNT_POS 12
#define AGG_TX_STATE_TRY_CNT_MSK 0xf000
+/* Command ID and sequence number of Tx command for this frame */
#define AGG_TX_STATE_SEQ_NUM_POS 16
#define AGG_TX_STATE_SEQ_NUM_MSK 0xffff0000
/*
* REPLY_TX = 0x1c (response)
+ *
+ * This response may be in one of two slightly different formats, indicated
+ * by the frame_count field:
+ *
+ * 1) No aggregation (frame_count == 1). This reports Tx results for
+ * a single frame. Multiple attempts, at various bit rates, may have
+ * been made for this frame.
+ *
+ * 2) Aggregation (frame_count > 1). This reports Tx results for
+ * 2 or more frames that used block-acknowledge. All frames were
+ * transmitted at same rate. Rate scaling may have been used if first
+ * frame in this new agg block failed in previous agg block(s).
+ *
+ * Note that, for aggregation, ACK (block-ack) status is not delivered here;
+ * block-ack has not been received by the time the 4965 records this status.
+ * This status relates to reasons the tx might have been blocked or aborted
+ * within the sending station (this 4965), rather than whether it was
+ * received successfully by the destination station.
*/
struct iwl4965_tx_resp {
u8 frame_count; /* 1 no aggregation, >1 aggregation */
- u8 bt_kill_count;
- u8 failure_rts;
- u8 failure_frame;
- __le32 rate_n_flags;
- __le16 wireless_media_time;
+ u8 bt_kill_count; /* # blocked by bluetooth (unused for agg) */
+ u8 failure_rts; /* # failures due to unsuccessful RTS */
+ u8 failure_frame; /* # failures due to no ACK (unused for agg) */
+
+ /* For non-agg: Rate at which frame was successful.
+ * For agg: Rate at which all frames were transmitted. */
+ __le32 rate_n_flags; /* RATE_MCS_* */
+
+ /* For non-agg: RTS + CTS + frame tx attempts time + ACK.
+ * For agg: RTS + CTS + aggregation tx time + block-ack time. */
+ __le16 wireless_media_time; /* uSecs */
+
__le16 reserved;
- __le32 pa_power1;
+ __le32 pa_power1; /* RF power amplifier measurement (not used) */
__le32 pa_power2;
+
+ /*
+ * For non-agg: frame status TX_STATUS_*
+ * For agg: status of 1st frame, AGG_TX_STATE_*; other frame status
+ * fields follow this one, up to frame_count.
+ * Bit fields:
+ * 11- 0: AGG_TX_STATE_* status code
+ * 15-12: Retry count for 1st frame in aggregation (retries
+ * occur if tx failed for this frame when it was a
+ * member of a previous aggregation block). If rate
+ * scaling is used, retry count indicates the rate
+ * table entry used for all frames in the new agg.
+ * 31-16: Sequence # for this frame's Tx cmd (not SSN!)
+ */
__le32 status; /* TX status (for aggregation status of 1st frame) */
} __attribute__ ((packed));
/*
* REPLY_COMPRESSED_BA = 0xc5 (response only, not a command)
+ *
+ * Reports Block-Acknowledge from recipient station
*/
struct iwl4965_compressed_ba_resp {
__le32 sta_addr_lo32;
__le16 sta_addr_hi16;
__le16 reserved;
+
+ /* Index of recipient (BA-sending) station in uCode's station table */
u8 sta_id;
u8 tid;
__le16 ba_seq_ctl;
/*
* REPLY_TX_PWR_TABLE_CMD = 0x97 (command, has simple generic response)
+ *
+ * See details under "TXPOWER" in iwl-4965-hw.h.
*/
struct iwl4965_txpowertable_cmd {
u8 band; /* 0: 5 GHz, 1: 2.4 GHz */
/*RS_NEW_API: only TLC_RTS remains and moved to bit 0 */
#define LINK_QUAL_FLAGS_SET_STA_TLC_RTS_MSK (1<<0)
+/* # of EDCA prioritized tx fifos */
#define LINK_QUAL_AC_NUM AC_NUM
+
+/* # entries in rate scale table to support Tx retries */
#define LINK_QUAL_MAX_RETRY_NUM 16
+/* Tx antenna selection values */
#define LINK_QUAL_ANT_A_MSK (1<<0)
#define LINK_QUAL_ANT_B_MSK (1<<1)
#define LINK_QUAL_ANT_MSK (LINK_QUAL_ANT_A_MSK|LINK_QUAL_ANT_B_MSK)
+
+/**
+ * struct iwl4965_link_qual_general_params
+ *
+ * Used in REPLY_TX_LINK_QUALITY_CMD
+ */
struct iwl4965_link_qual_general_params {
u8 flags;
+
+ /* No entries at or above this (driver chosen) index contain MIMO */
u8 mimo_delimiter;
- u8 single_stream_ant_msk;
- u8 dual_stream_ant_msk;
+
+ /* Best single antenna to use for single stream (legacy, SISO). */
+ u8 single_stream_ant_msk; /* LINK_QUAL_ANT_* */
+
+ /* Best antennas to use for MIMO (unused for 4965, assumes both). */
+ u8 dual_stream_ant_msk; /* LINK_QUAL_ANT_* */
+
+ /*
+ * If driver needs to use different initial rates for different
+ * EDCA QOS access categories (as implemented by tx fifos 0-3),
+ * this table will set that up, by indicating the indexes in the
+ * rs_table[LINK_QUAL_MAX_RETRY_NUM] rate table at which to start.
+ * Otherwise, driver should set all entries to 0.
+ *
+ * Entry usage:
+ * 0 = Background, 1 = Best Effort (normal), 2 = Video, 3 = Voice
+ * TX FIFOs above 3 use same value (typically 0) as TX FIFO 3.
+ */
u8 start_rate_index[LINK_QUAL_AC_NUM];
} __attribute__ ((packed));
+/**
+ * struct iwl4965_link_qual_agg_params
+ *
+ * Used in REPLY_TX_LINK_QUALITY_CMD
+ */
struct iwl4965_link_qual_agg_params {
+
+ /* Maximum number of uSec in aggregation.
+ * Driver should set this to 4000 (4 milliseconds). */
__le16 agg_time_limit;
+
+ /*
+ * Number of Tx retries allowed for a frame, before that frame will
+ * no longer be considered for the start of an aggregation sequence
+ * (scheduler will then try to tx it as single frame).
+ * Driver should set this to 3.
+ */
u8 agg_dis_start_th;
+
+ /*
+ * Maximum number of frames in aggregation.
+ * 0 = no limit (default). 1 = no aggregation.
+ * Other values = max # frames in aggregation.
+ */
u8 agg_frame_cnt_limit;
+
__le32 reserved;
} __attribute__ ((packed));
/*
* REPLY_TX_LINK_QUALITY_CMD = 0x4e (command, has simple generic response)
+ *
+ * For 4965 only; 3945 uses REPLY_RATE_SCALE.
+ *
+ * Each station in the 4965's internal station table has its own table of 16
+ * Tx rates and modulation modes (e.g. legacy/SISO/MIMO) for retrying Tx when
+ * an ACK is not received. This command replaces the entire table for
+ * one station.
+ *
+ * NOTE: Station must already be in 4965's station table. Use REPLY_ADD_STA.
+ *
+ * The rate scaling procedures described below work well. Of course, other
+ * procedures are possible, and may work better for particular environments.
+ *
+ *
+ * FILLING THE RATE TABLE
+ *
+ * Given a particular initial rate and mode, as determined by the rate
+ * scaling algorithm described below, the Linux driver uses the following
+ * formula to fill the rs_table[LINK_QUAL_MAX_RETRY_NUM] rate table in the
+ * Link Quality command:
+ *
+ *
+ * 1) If using High-throughput (HT) (SISO or MIMO) initial rate:
+ * a) Use this same initial rate for first 3 entries.
+ * b) Find next lower available rate using same mode (SISO or MIMO),
+ * use for next 3 entries. If no lower rate available, switch to
+ * legacy mode (no FAT channel, no MIMO, no short guard interval).
+ * c) If using MIMO, set command's mimo_delimiter to number of entries
+ * using MIMO (3 or 6).
+ * d) After trying 2 HT rates, switch to legacy mode (no FAT channel,
+ * no MIMO, no short guard interval), at the next lower bit rate
+ * (e.g. if second HT bit rate was 54, try 48 legacy), and follow
+ * legacy procedure for remaining table entries.
+ *
+ * 2) If using legacy initial rate:
+ * a) Use the initial rate for only one entry.
+ * b) For each following entry, reduce the rate to next lower available
+ * rate, until reaching the lowest available rate.
+ * c) When reducing rate, also switch antenna selection.
+ * d) Once lowest available rate is reached, repeat this rate until
+ * rate table is filled (16 entries), switching antenna each entry.
+ *
+ *
+ * ACCUMULATING HISTORY
+ *
+ * The rate scaling algorithm for 4965, as implemented in Linux driver, uses
+ * two sets of frame Tx success history: One for the current/active modulation
+ * mode, and one for a speculative/search mode that is being attempted. If the
+ * speculative mode turns out to be more effective (i.e. actual transfer
+ * rate is better), then the driver continues to use the speculative mode
+ * as the new current active mode.
+ *
+ * Each history set contains, separately for each possible rate, data for a
+ * sliding window of the 62 most recent tx attempts at that rate. The data
+ * includes a shifting bitmap of success(1)/failure(0), and sums of successful
+ * and attempted frames, from which the driver can additionally calculate a
+ * success ratio (success / attempted) and number of failures
+ * (attempted - success), and control the size of the window (attempted).
+ * The driver uses the bit map to remove successes from the success sum, as
+ * the oldest tx attempts fall out of the window.
+ *
+ * When the 4965 makes multiple tx attempts for a given frame, each attempt
+ * might be at a different rate, and have different modulation characteristics
+ * (e.g. antenna, fat channel, short guard interval), as set up in the rate
+ * scaling table in the Link Quality command. The driver must determine
+ * which rate table entry was used for each tx attempt, to determine which
+ * rate-specific history to update, and record only those attempts that
+ * match the modulation characteristics of the history set.
+ *
+ * When using block-ack (aggregation), all frames are transmitted at the same
+ * rate, since there is no per-attempt acknowledgement from the destination
+ * station. The Tx response struct iwl_tx_resp indicates the Tx rate in
+ * rate_n_flags field. After receiving a block-ack, the driver can update
+ * history for the entire block all at once.
+ *
+ *
+ * FINDING BEST STARTING RATE:
+ *
+ * When working with a selected initial modulation mode (see below), the
+ * driver attempts to find a best initial rate. The initial rate is the
+ * first entry in the Link Quality command's rate table.
+ *
+ * 1) Calculate actual throughput (success ratio * expected throughput, see
+ * table below) for current initial rate. Do this only if enough frames
+ * have been attempted to make the value meaningful: at least 6 failed
+ * tx attempts, or at least 8 successes. If not enough, don't try rate
+ * scaling yet.
+ *
+ * 2) Find available rates adjacent to current initial rate. Available means:
+ * a) supported by hardware &&
+ * b) supported by association &&
+ * c) within any constraints selected by user
+ *
+ * 3) Gather measured throughputs for adjacent rates. These might not have
+ * enough history to calculate a throughput. That's okay, we might try
+ * using one of them anyway!
+ *
+ * 4) Try decreasing rate if, for current rate:
+ * a) success ratio is < 15% ||
+ * b) lower adjacent rate has better measured throughput ||
+ * c) higher adjacent rate has worse throughput, and lower is unmeasured
+ *
+ * As a sanity check, if decrease was determined above, leave rate
+ * unchanged if:
+ * a) lower rate unavailable
+ * b) success ratio at current rate > 85% (very good)
+ * c) current measured throughput is better than expected throughput
+ * of lower rate (under perfect 100% tx conditions, see table below)
+ *
+ * 5) Try increasing rate if, for current rate:
+ * a) success ratio is < 15% ||
+ * b) both adjacent rates' throughputs are unmeasured (try it!) ||
+ * b) higher adjacent rate has better measured throughput ||
+ * c) lower adjacent rate has worse throughput, and higher is unmeasured
+ *
+ * As a sanity check, if increase was determined above, leave rate
+ * unchanged if:
+ * a) success ratio at current rate < 70%. This is not particularly
+ * good performance; higher rate is sure to have poorer success.
+ *
+ * 6) Re-evaluate the rate after each tx frame. If working with block-
+ * acknowledge, history and statistics may be calculated for the entire
+ * block (including prior history that fits within the history windows),
+ * before re-evaluation.
+ *
+ * FINDING BEST STARTING MODULATION MODE:
+ *
+ * After working with a modulation mode for a "while" (and doing rate scaling),
+ * the driver searches for a new initial mode in an attempt to improve
+ * throughput. The "while" is measured by numbers of attempted frames:
+ *
+ * For legacy mode, search for new mode after:
+ * 480 successful frames, or 160 failed frames
+ * For high-throughput modes (SISO or MIMO), search for new mode after:
+ * 4500 successful frames, or 400 failed frames
+ *
+ * Mode switch possibilities are (3 for each mode):
+ *
+ * For legacy:
+ * Change antenna, try SISO (if HT association), try MIMO (if HT association)
+ * For SISO:
+ * Change antenna, try MIMO, try shortened guard interval (SGI)
+ * For MIMO:
+ * Try SISO antenna A, SISO antenna B, try shortened guard interval (SGI)
+ *
+ * When trying a new mode, use the same bit rate as the old/current mode when
+ * trying antenna switches and shortened guard interval. When switching to
+ * SISO from MIMO or legacy, or to MIMO from SISO or legacy, use a rate
+ * for which the expected throughput (under perfect conditions) is about the
+ * same or slightly better than the actual measured throughput delivered by
+ * the old/current mode.
+ *
+ * Actual throughput can be estimated by multiplying the expected throughput
+ * by the success ratio (successful / attempted tx frames). Frame size is
+ * not considered in this calculation; it assumes that frame size will average
+ * out to be fairly consistent over several samples. The following are
+ * metric values for expected throughput assuming 100% success ratio.
+ * Only G band has support for CCK rates:
+ *
+ * RATE: 1 2 5 11 6 9 12 18 24 36 48 54 60
+ *
+ * G: 7 13 35 58 40 57 72 98 121 154 177 186 186
+ * A: 0 0 0 0 40 57 72 98 121 154 177 186 186
+ * SISO 20MHz: 0 0 0 0 42 42 76 102 124 159 183 193 202
+ * SGI SISO 20MHz: 0 0 0 0 46 46 82 110 132 168 192 202 211
+ * MIMO 20MHz: 0 0 0 0 74 74 123 155 179 214 236 244 251
+ * SGI MIMO 20MHz: 0 0 0 0 81 81 131 164 188 222 243 251 257
+ * SISO 40MHz: 0 0 0 0 77 77 127 160 184 220 242 250 257
+ * SGI SISO 40MHz: 0 0 0 0 83 83 135 169 193 229 250 257 264
+ * MIMO 40MHz: 0 0 0 0 123 123 182 214 235 264 279 285 289
+ * SGI MIMO 40MHz: 0 0 0 0 131 131 191 222 242 270 284 289 293
+ *
+ * After the new mode has been tried for a short while (minimum of 6 failed
+ * frames or 8 successful frames), compare success ratio and actual throughput
+ * estimate of the new mode with the old. If either is better with the new
+ * mode, continue to use the new mode.
+ *
+ * Continue comparing modes until all 3 possibilities have been tried.
+ * If moving from legacy to HT, try all 3 possibilities from the new HT
+ * mode. After trying all 3, a best mode is found. Continue to use this mode
+ * for the longer "while" described above (e.g. 480 successful frames for
+ * legacy), and then repeat the search process.
+ *
*/
struct iwl4965_link_quality_cmd {
+
+ /* Index of destination/recipient station in uCode's station table */
u8 sta_id;
u8 reserved1;
- __le16 control;
+ __le16 control; /* not used */
struct iwl4965_link_qual_general_params general_params;
struct iwl4965_link_qual_agg_params agg_params;
+
+ /*
+ * Rate info; when using rate-scaling, Tx command's initial_rate_index
+ * specifies 1st Tx rate attempted, via index into this table.
+ * 4965 works its way through table when retrying Tx.
+ */
struct {
- __le32 rate_n_flags;
+ __le32 rate_n_flags; /* RATE_MCS_*, IWL_RATE_* */
} rs_table[LINK_QUAL_MAX_RETRY_NUM];
__le32 reserved2;
} __attribute__ ((packed));
projects / linux-2.6 / blobdiff