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Date: Mon, 1 Jul 2019 13:09:46 +0800
From: Chris Chiu <chiu@...lessm.com>
To: Jes Sorensen <jes.sorensen@...il.com>,
Kalle Valo <kvalo@...eaurora.org>,
David Miller <davem@...emloft.net>
Cc: linux-wireless <linux-wireless@...r.kernel.org>,
netdev <netdev@...r.kernel.org>,
Linux Kernel <linux-kernel@...r.kernel.org>,
Linux Upstreaming Team <linux@...lessm.com>
Subject: Re: [RFC PATCH v5] rtl8xxxu: Improve TX performance of RTL8723BU on
rtl8xxxu driver
On Mon, Jun 17, 2019 at 2:56 PM Chris Chiu <chiu@...lessm.com> wrote:
>
> We have 3 laptops which connect the wifi by the same RTL8723BU.
> The PCI VID/PID of the wifi chip is 10EC:B720 which is supported.
> They have the same problem with the in-kernel rtl8xxxu driver, the
> iperf (as a client to an ethernet-connected server) gets ~1Mbps.
> Nevertheless, the signal strength is reported as around -40dBm,
> which is quite good. From the wireshark capture, the tx rate for each
> data and qos data packet is only 1Mbps. Compare to the Realtek driver
> at https://github.com/lwfinger/rtl8723bu, the same iperf test gets
> ~12Mbps or better. The signal strength is reported similarly around
> -40dBm. That's why we want to improve.
>
> After reading the source code of the rtl8xxxu driver and Realtek's, the
> major difference is that Realtek's driver has a watchdog which will keep
> monitoring the signal quality and updating the rate mask just like the
> rtl8xxxu_gen2_update_rate_mask() does if signal quality changes.
> And this kind of watchdog also exists in rtlwifi driver of some specific
> chips, ex rtl8192ee, rtl8188ee, rtl8723ae, rtl8821ae...etc. They have
> the same member function named dm_watchdog and will invoke the
> corresponding dm_refresh_rate_adaptive_mask to adjust the tx rate
> mask.
>
> With this commit, the tx rate of each data and qos data packet will
> be 39Mbps (MCS4) with the 0xF00000 as the tx rate mask. The 20th bit
> to 23th bit means MCS4 to MCS7. It means that the firmware still picks
> the lowest rate from the rate mask and explains why the tx rate of
> data and qos data is always lowest 1Mbps because the default rate mask
> passed is always 0xFFFFFFF ranges from the basic CCK rate, OFDM rate,
> and MCS rate. However, with Realtek's driver, the tx rate observed from
> wireshark under the same condition is almost 65Mbps or 72Mbps.
>
> I believe the firmware of RTL8723BU may need fix. And I think we
> can still bring in the dm_watchdog as rtlwifi to improve from the
> driver side. Please leave precious comments for my commits and
> suggest what I can do better. Or suggest if there's any better idea
> to fix this. Thanks.
>
> Signed-off-by: Chris Chiu <chiu@...lessm.com>
> ---
>
>
> Notes:
> v2:
> - Fix errors and warnings complained by checkpatch.pl
> - Replace data structure rate_adaptive by 2 member variables
> - Make rtl8xxxu_wireless_mode non-static
> - Runs refresh_rate_mask() only in station mode
> v3:
> - Remove ugly rtl8xxxu_watchdog data structure
> - Make sure only one vif exists
> v4:
> - Move cancel_delayed_work from rtl8xxxu_disconnect to rtl8xxxu_stop
> - Clear priv->vif in rtl8xxxu_remove_interface
> - Add rateid as the function argument of update_rate_mask
> - Rephrase the comment for priv->vif more explicit.
> v5:
> - Make refresh_rate_mask() generic for all sub-drivers.
> - Add definitions for SNR related to help determine rssi_level
>
>
> .../net/wireless/realtek/rtl8xxxu/rtl8xxxu.h | 55 ++++-
> .../wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 226 +++++++++++++++++-
> 2 files changed, 274 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
> index 8828baf26e7b..1498a8c94d5f 100644
> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu.h
> @@ -1195,6 +1195,48 @@ struct rtl8723bu_c2h {
>
> struct rtl8xxxu_fileops;
>
> +/*mlme related.*/
> +enum wireless_mode {
> + WIRELESS_MODE_UNKNOWN = 0,
> + /* Sub-Element */
> + WIRELESS_MODE_B = BIT(0),
> + WIRELESS_MODE_G = BIT(1),
> + WIRELESS_MODE_A = BIT(2),
> + WIRELESS_MODE_N_24G = BIT(3),
> + WIRELESS_MODE_N_5G = BIT(4),
> + WIRELESS_AUTO = BIT(5),
> + WIRELESS_MODE_AC = BIT(6),
> + WIRELESS_MODE_MAX = 0x7F,
> +};
> +
> +/* from rtlwifi/wifi.h */
> +enum ratr_table_mode_new {
> + RATEID_IDX_BGN_40M_2SS = 0,
> + RATEID_IDX_BGN_40M_1SS = 1,
> + RATEID_IDX_BGN_20M_2SS_BN = 2,
> + RATEID_IDX_BGN_20M_1SS_BN = 3,
> + RATEID_IDX_GN_N2SS = 4,
> + RATEID_IDX_GN_N1SS = 5,
> + RATEID_IDX_BG = 6,
> + RATEID_IDX_G = 7,
> + RATEID_IDX_B = 8,
> + RATEID_IDX_VHT_2SS = 9,
> + RATEID_IDX_VHT_1SS = 10,
> + RATEID_IDX_MIX1 = 11,
> + RATEID_IDX_MIX2 = 12,
> + RATEID_IDX_VHT_3SS = 13,
> + RATEID_IDX_BGN_3SS = 14,
> +};
> +
> +#define RTL8XXXU_RATR_STA_INIT 0
> +#define RTL8XXXU_RATR_STA_HIGH 1
> +#define RTL8XXXU_RATR_STA_MID 2
> +#define RTL8XXXU_RATR_STA_LOW 3
> +
> +#define RTL8XXXU_NOISE_FLOOR_MIN -95
> +#define RTL8XXXU_SNR_THRESH_HIGH 50
> +#define RTL8XXXU_SNR_THRESH_LOW 20
> +
> struct rtl8xxxu_priv {
> struct ieee80211_hw *hw;
> struct usb_device *udev;
> @@ -1299,6 +1341,13 @@ struct rtl8xxxu_priv {
> u8 pi_enabled:1;
> u8 no_pape:1;
> u8 int_buf[USB_INTR_CONTENT_LENGTH];
> + u8 rssi_level;
> + /*
> + * Only one virtual interface permitted because only STA mode
> + * is supported and no iface_combinations are providec.
> + */
> + struct ieee80211_vif *vif;
> + struct delayed_work ra_watchdog;
> };
>
> struct rtl8xxxu_rx_urb {
> @@ -1334,7 +1383,7 @@ struct rtl8xxxu_fileops {
> void (*set_tx_power) (struct rtl8xxxu_priv *priv, int channel,
> bool ht40);
> void (*update_rate_mask) (struct rtl8xxxu_priv *priv,
> - u32 ramask, int sgi);
> + u32 ramask, u8 rateid, int sgi);
> void (*report_connect) (struct rtl8xxxu_priv *priv,
> u8 macid, bool connect);
> void (*fill_txdesc) (struct ieee80211_hw *hw, struct ieee80211_hdr *hdr,
> @@ -1419,9 +1468,9 @@ void rtl8xxxu_gen2_config_channel(struct ieee80211_hw *hw);
> void rtl8xxxu_gen1_usb_quirks(struct rtl8xxxu_priv *priv);
> void rtl8xxxu_gen2_usb_quirks(struct rtl8xxxu_priv *priv);
> void rtl8xxxu_update_rate_mask(struct rtl8xxxu_priv *priv,
> - u32 ramask, int sgi);
> + u32 ramask, u8 rateid, int sgi);
> void rtl8xxxu_gen2_update_rate_mask(struct rtl8xxxu_priv *priv,
> - u32 ramask, int sgi);
> + u32 ramask, u8 rateid, int sgi);
> void rtl8xxxu_gen1_report_connect(struct rtl8xxxu_priv *priv,
> u8 macid, bool connect);
> void rtl8xxxu_gen2_report_connect(struct rtl8xxxu_priv *priv,
> diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> index 039e5ca9d2e4..474dea2291a9 100644
> --- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> +++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
> @@ -4311,7 +4311,8 @@ static void rtl8xxxu_sw_scan_complete(struct ieee80211_hw *hw,
> rtl8xxxu_write8(priv, REG_BEACON_CTRL, val8);
> }
>
> -void rtl8xxxu_update_rate_mask(struct rtl8xxxu_priv *priv, u32 ramask, int sgi)
> +void rtl8xxxu_update_rate_mask(struct rtl8xxxu_priv *priv,
> + u32 ramask, u8 rateid, int sgi)
> {
> struct h2c_cmd h2c;
>
> @@ -4331,7 +4332,7 @@ void rtl8xxxu_update_rate_mask(struct rtl8xxxu_priv *priv, u32 ramask, int sgi)
> }
>
> void rtl8xxxu_gen2_update_rate_mask(struct rtl8xxxu_priv *priv,
> - u32 ramask, int sgi)
> + u32 ramask, u8 rateid, int sgi)
> {
> struct h2c_cmd h2c;
> u8 bw = 0;
> @@ -4345,7 +4346,7 @@ void rtl8xxxu_gen2_update_rate_mask(struct rtl8xxxu_priv *priv,
> h2c.b_macid_cfg.ramask3 = (ramask >> 24) & 0xff;
>
> h2c.ramask.arg = 0x80;
> - h2c.b_macid_cfg.data1 = 0;
> + h2c.b_macid_cfg.data1 = rateid;
> if (sgi)
> h2c.b_macid_cfg.data1 |= BIT(7);
>
> @@ -4485,6 +4486,40 @@ static void rtl8xxxu_set_basic_rates(struct rtl8xxxu_priv *priv, u32 rate_cfg)
> rtl8xxxu_write8(priv, REG_INIRTS_RATE_SEL, rate_idx);
> }
>
> +static u16
> +rtl8xxxu_wireless_mode(struct ieee80211_hw *hw, struct ieee80211_sta *sta)
> +{
> + u16 network_type = WIRELESS_MODE_UNKNOWN;
> + u32 rate_mask;
> +
> + rate_mask = (sta->supp_rates[0] & 0xfff) |
> + (sta->ht_cap.mcs.rx_mask[0] << 12) |
> + (sta->ht_cap.mcs.rx_mask[0] << 20);
> +
> + if (hw->conf.chandef.chan->band == NL80211_BAND_5GHZ) {
> + if (sta->vht_cap.vht_supported)
> + network_type = WIRELESS_MODE_AC;
> + else if (sta->ht_cap.ht_supported)
> + network_type = WIRELESS_MODE_N_5G;
> +
> + network_type |= WIRELESS_MODE_A;
> + } else {
> + if (sta->vht_cap.vht_supported)
> + network_type = WIRELESS_MODE_AC;
> + else if (sta->ht_cap.ht_supported)
> + network_type = WIRELESS_MODE_N_24G;
> +
> + if (sta->supp_rates[0] <= 0xf)
> + network_type |= WIRELESS_MODE_B;
> + else if (sta->supp_rates[0] & 0xf)
> + network_type |= (WIRELESS_MODE_B | WIRELESS_MODE_G);
> + else
> + network_type |= WIRELESS_MODE_G;
> + }
> +
> + return network_type;
> +}
> +
> static void
> rtl8xxxu_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> struct ieee80211_bss_conf *bss_conf, u32 changed)
> @@ -4527,7 +4562,10 @@ rtl8xxxu_bss_info_changed(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> sgi = 1;
> rcu_read_unlock();
>
> - priv->fops->update_rate_mask(priv, ramask, sgi);
> + priv->vif = vif;
> + priv->rssi_level = RTL8XXXU_RATR_STA_INIT;
> +
> + priv->fops->update_rate_mask(priv, ramask, 0, sgi);
>
> rtl8xxxu_write8(priv, REG_BCN_MAX_ERR, 0xff);
>
> @@ -5471,6 +5509,10 @@ static int rtl8xxxu_add_interface(struct ieee80211_hw *hw,
>
> switch (vif->type) {
> case NL80211_IFTYPE_STATION:
> + if (!priv->vif)
> + priv->vif = vif;
> + else
> + return -EOPNOTSUPP;
> rtl8xxxu_stop_tx_beacon(priv);
>
> val8 = rtl8xxxu_read8(priv, REG_BEACON_CTRL);
> @@ -5494,6 +5536,9 @@ static void rtl8xxxu_remove_interface(struct ieee80211_hw *hw,
> struct rtl8xxxu_priv *priv = hw->priv;
>
> dev_dbg(&priv->udev->dev, "%s\n", __func__);
> +
> + if (priv->vif)
> + priv->vif = NULL;
> }
>
> static int rtl8xxxu_config(struct ieee80211_hw *hw, u32 changed)
> @@ -5779,6 +5824,174 @@ rtl8xxxu_ampdu_action(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
> return 0;
> }
>
> +static u8 rtl8xxxu_signal_to_snr(int signal)
> +{
> + if (signal < RTL8XXXU_NOISE_FLOOR_MIN)
> + signal = RTL8XXXU_NOISE_FLOOR_MIN;
> + return (u8)(signal - RTL8XXXU_NOISE_FLOOR_MIN);
> +}
> +
> +static void rtl8xxxu_refresh_rate_mask(struct rtl8xxxu_priv *priv,
> + int signal, struct ieee80211_sta *sta)
> +{
> + struct ieee80211_hw *hw = priv->hw;
> + u16 wireless_mode;
> + u8 rssi_level, ratr_idx;
> + u8 txbw_40mhz;
> + u8 snr, snr_thresh_high, snr_thresh_low;
> + u8 go_up_gap = 5;
> +
> + rssi_level = priv->rssi_level;
> + snr = rtl8xxxu_signal_to_snr(signal);
> + snr_thresh_high = RTL8XXXU_SNR_THRESH_HIGH;
> + snr_thresh_low = RTL8XXXU_SNR_THRESH_LOW;
> + txbw_40mhz = (hw->conf.chandef.width == NL80211_CHAN_WIDTH_40) ? 1 : 0;
> +
> + switch (rssi_level) {
> + case RTL8XXXU_RATR_STA_MID:
> + snr_thresh_high += go_up_gap;
> + break;
> + case RTL8XXXU_RATR_STA_LOW:
> + snr_thresh_high += go_up_gap;
> + snr_thresh_low += go_up_gap;
> + break;
> + default:
> + break;
> + }
> +
> + if (snr > snr_thresh_high)
> + rssi_level = RTL8XXXU_RATR_STA_HIGH;
> + else if (snr > snr_thresh_low)
> + rssi_level = RTL8XXXU_RATR_STA_MID;
> + else
> + rssi_level = RTL8XXXU_RATR_STA_LOW;
> +
> + if (rssi_level != priv->rssi_level) {
> + int sgi = 0;
> + u32 rate_bitmap = 0;
> +
> + rcu_read_lock();
> + rate_bitmap = (sta->supp_rates[0] & 0xfff) |
> + (sta->ht_cap.mcs.rx_mask[0] << 12) |
> + (sta->ht_cap.mcs.rx_mask[1] << 20);
> + if (sta->ht_cap.cap &
> + (IEEE80211_HT_CAP_SGI_40 | IEEE80211_HT_CAP_SGI_20))
> + sgi = 1;
> + rcu_read_unlock();
> +
> + wireless_mode = rtl8xxxu_wireless_mode(hw, sta);
> + switch (wireless_mode) {
> + case WIRELESS_MODE_B:
> + ratr_idx = RATEID_IDX_B;
> + if (rate_bitmap & 0x0000000c)
> + rate_bitmap &= 0x0000000d;
> + else
> + rate_bitmap &= 0x0000000f;
> + break;
> + case WIRELESS_MODE_A:
> + case WIRELESS_MODE_G:
> + ratr_idx = RATEID_IDX_G;
> + if (rssi_level == RTL8XXXU_RATR_STA_HIGH)
> + rate_bitmap &= 0x00000f00;
> + else
> + rate_bitmap &= 0x00000ff0;
> + break;
> + case (WIRELESS_MODE_B | WIRELESS_MODE_G):
> + ratr_idx = RATEID_IDX_BG;
> + if (rssi_level == RTL8XXXU_RATR_STA_HIGH)
> + rate_bitmap &= 0x00000f00;
> + else if (rssi_level == RTL8XXXU_RATR_STA_MID)
> + rate_bitmap &= 0x00000ff0;
> + else
> + rate_bitmap &= 0x00000ff5;
> + break;
> + case WIRELESS_MODE_N_24G:
> + case WIRELESS_MODE_N_5G:
> + case (WIRELESS_MODE_G | WIRELESS_MODE_N_24G):
> + case (WIRELESS_MODE_A | WIRELESS_MODE_N_5G):
> + if (priv->tx_paths == 2 && priv->rx_paths == 2)
> + ratr_idx = RATEID_IDX_GN_N2SS;
> + else
> + ratr_idx = RATEID_IDX_GN_N1SS;
> + case (WIRELESS_MODE_B | WIRELESS_MODE_G | WIRELESS_MODE_N_24G):
> + case (WIRELESS_MODE_B | WIRELESS_MODE_N_24G):
> + if (txbw_40mhz) {
> + if (priv->tx_paths == 2 && priv->rx_paths == 2)
> + ratr_idx = RATEID_IDX_BGN_40M_2SS;
> + else
> + ratr_idx = RATEID_IDX_BGN_40M_1SS;
> + } else {
> + if (priv->tx_paths == 2 && priv->rx_paths == 2)
> + ratr_idx = RATEID_IDX_BGN_20M_2SS_BN;
> + else
> + ratr_idx = RATEID_IDX_BGN_20M_1SS_BN;
> + }
> +
> + if (priv->tx_paths == 2 && priv->rx_paths == 2) {
> + if (rssi_level == RTL8XXXU_RATR_STA_HIGH) {
> + rate_bitmap &= 0x0f8f0000;
> + } else if (rssi_level == RTL8XXXU_RATR_STA_MID) {
> + rate_bitmap &= 0x0f8ff000;
> + } else {
> + if (txbw_40mhz)
> + rate_bitmap &= 0x0f8ff015;
> + else
> + rate_bitmap &= 0x0f8ff005;
> + }
> + } else {
> + if (rssi_level == RTL8XXXU_RATR_STA_HIGH) {
> + rate_bitmap &= 0x000f0000;
> + } else if (rssi_level == RTL8XXXU_RATR_STA_MID) {
> + rate_bitmap &= 0x000ff000;
> + } else {
> + if (txbw_40mhz)
> + rate_bitmap &= 0x000ff015;
> + else
> + rate_bitmap &= 0x000ff005;
> + }
> + }
> + break;
> + default:
> + ratr_idx = RATEID_IDX_BGN_40M_2SS;
> + rate_bitmap &= 0x0fffffff;
> + break;
> + }
> +
> + priv->rssi_level = rssi_level;
> + priv->fops->update_rate_mask(priv, rate_bitmap, ratr_idx, sgi);
> + }
> +}
> +
> +static void rtl8xxxu_watchdog_callback(struct work_struct *work)
> +{
> + struct ieee80211_vif *vif;
> + struct rtl8xxxu_priv *priv;
> +
> + priv = container_of(work, struct rtl8xxxu_priv, ra_watchdog.work);
> + vif = priv->vif;
> +
> + if (vif && vif->type == NL80211_IFTYPE_STATION) {
> + int signal;
> + struct ieee80211_sta *sta;
> +
> + rcu_read_lock();
> + sta = ieee80211_find_sta(vif, vif->bss_conf.bssid);
> + if (!sta) {
> + struct device *dev = &priv->udev->dev;
> +
> + dev_info(dev, "%s: no sta found\n", __func__);
> + rcu_read_unlock();
> + return;
> + }
> + rcu_read_unlock();
> +
> + signal = ieee80211_ave_rssi(vif);
> + rtl8xxxu_refresh_rate_mask(priv, signal, sta);
> + }
> +
> + schedule_delayed_work(&priv->ra_watchdog, 2 * HZ);
> +}
> +
> static int rtl8xxxu_start(struct ieee80211_hw *hw)
> {
> struct rtl8xxxu_priv *priv = hw->priv;
> @@ -5835,6 +6048,8 @@ static int rtl8xxxu_start(struct ieee80211_hw *hw)
>
> ret = rtl8xxxu_submit_rx_urb(priv, rx_urb);
> }
> +
> + schedule_delayed_work(&priv->ra_watchdog, 2 * HZ);
> exit:
> /*
> * Accept all data and mgmt frames
> @@ -5886,6 +6101,8 @@ static void rtl8xxxu_stop(struct ieee80211_hw *hw)
> if (priv->usb_interrupts)
> rtl8xxxu_write32(priv, REG_USB_HIMR, 0);
>
> + cancel_delayed_work_sync(&priv->ra_watchdog);
> +
> rtl8xxxu_free_rx_resources(priv);
> rtl8xxxu_free_tx_resources(priv);
> }
> @@ -6058,6 +6275,7 @@ static int rtl8xxxu_probe(struct usb_interface *interface,
> INIT_LIST_HEAD(&priv->rx_urb_pending_list);
> spin_lock_init(&priv->rx_urb_lock);
> INIT_WORK(&priv->rx_urb_wq, rtl8xxxu_rx_urb_work);
> + INIT_DELAYED_WORK(&priv->ra_watchdog, rtl8xxxu_watchdog_callback);
>
> usb_set_intfdata(interface, hw);
>
> --
> 2.21.0
>
Gentle ping. Cheers.
Chris
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