This is a note to let you know that I've just added the patch titled
wifi: rtl8xxxu: Use a longer retry limit of 48
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
wifi-rtl8xxxu-use-a-longer-retry-limit-of-48.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 2a86aa9a1892d60ef2e3f310f5b42b8b05546d65 Mon Sep 17 00:00:00 2001
From: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
Date: Sun, 8 Jan 2023 17:08:16 +0200
Subject: wifi: rtl8xxxu: Use a longer retry limit of 48
From: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
commit 2a86aa9a1892d60ef2e3f310f5b42b8b05546d65 upstream.
The Realtek rate control algorithm goes back and forth a lot between
the highest and the lowest rate it's allowed to use. This is due to
a lot of frames being dropped because the retry limits set by
IEEE80211_CONF_CHANGE_RETRY_LIMITS are too low. (Experimentally, they
are 4 for long frames and 7 for short frames.)
The vendor drivers hardcode the value 48 for both retry limits (for
station mode), which makes dropped frames very rare and thus the rate
control is more stable.
Because most Realtek chips handle the rate control in the firmware,
which can't be modified, ignore the limits set by
IEEE80211_CONF_CHANGE_RETRY_LIMITS and use the value 48 (set during
chip initialisation), same as the vendor drivers.
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Bitterblue Smith <rtl8821cerfe2@xxxxxxxxx>
Reviewed-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
Signed-off-by: Kalle Valo <kvalo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/477d745b-6bac-111d-403c-487fc19aa30d@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 9 ---------
1 file changed, 9 deletions(-)
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -5500,7 +5500,6 @@ static int rtl8xxxu_config(struct ieee80
{
struct rtl8xxxu_priv *priv = hw->priv;
struct device *dev = &priv->udev->dev;
- u16 val16;
int ret = 0, channel;
bool ht40;
@@ -5510,14 +5509,6 @@ static int rtl8xxxu_config(struct ieee80
__func__, hw->conf.chandef.chan->hw_value,
changed, hw->conf.chandef.width);
- if (changed & IEEE80211_CONF_CHANGE_RETRY_LIMITS) {
- val16 = ((hw->conf.long_frame_max_tx_count <<
- RETRY_LIMIT_LONG_SHIFT) & RETRY_LIMIT_LONG_MASK) |
- ((hw->conf.short_frame_max_tx_count <<
- RETRY_LIMIT_SHORT_SHIFT) & RETRY_LIMIT_SHORT_MASK);
- rtl8xxxu_write16(priv, REG_RETRY_LIMIT, val16);
- }
-
if (changed & IEEE80211_CONF_CHANGE_CHANNEL) {
switch (hw->conf.chandef.width) {
case NL80211_CHAN_WIDTH_20_NOHT:
Patches currently in stable-queue which might be from rtl8821cerfe2@xxxxxxxxx are
queue-4.19/wifi-rtl8xxxu-use-a-longer-retry-limit-of-48.patch
