[OpenWrt-Devel] [PATCH 1/2] ath5k: channel change fix
Sergey Ryazanov
ryazanov.s.a at gmail.com
Tue Mar 3 21:47:01 EST 2015
Signed-off-by: Sergey Ryazanov <ryazanov.s.a at gmail.com>
---
.../patches/331-ath5k-channel-change-fix.patch | 145 +++++++++++++++++++++
1 file changed, 145 insertions(+)
create mode 100644 package/kernel/mac80211/patches/331-ath5k-channel-change-fix.patch
diff --git a/package/kernel/mac80211/patches/331-ath5k-channel-change-fix.patch b/package/kernel/mac80211/patches/331-ath5k-channel-change-fix.patch
new file mode 100644
index 0000000..e776063
--- /dev/null
+++ b/package/kernel/mac80211/patches/331-ath5k-channel-change-fix.patch
@@ -0,0 +1,145 @@
+From a5d37f41d298a2a202296909892dd01e2bf071c7 Mon Sep 17 00:00:00 2001
+From: Sergey Ryazanov <ryazanov.s.a at gmail.com>
+Date: Wed, 4 Mar 2015 00:44:37 +0300
+Subject: [PATCH] ath5k: channel change fix
+
+ath5k updates the channel pointer and after that it stops the Rx logic
+and apply channel to HW. In case of channel switch, such sequence
+creates a small window when a frame, which is received on the old
+channel is considered as a frame received on the new one.
+
+The most notable consequence of this situation occurs during the switch
+from 2 GHz band (CCK+OFDM) to the 5GHz band (OFDM-only). Frame received
+with CCK rate, e.g. beacon received at the 1mbps, causes the following
+warning:
+
+ WARNING: at ath5k/base.c:589 ath5k_tasklet_rx+0x318/0x6ec [ath5k]()
+ invalid hw_rix: 1a
+ [..]
+ Call Trace:
+ [<802656a8>] show_stack+0x48/0x70
+ [<802dd92c>] warn_slowpath_common+0x88/0xbc
+ [<802dd98c>] warn_slowpath_fmt+0x2c/0x38
+ [<81b51be8>] ath5k_tasklet_rx+0x318/0x6ec [ath5k]
+ [<8028ac64>] tasklet_action+0x8c/0xf0
+ [<80075804>] __do_softirq+0x180/0x32c
+ [<80196ce8>] irq_exit+0x54/0x70
+ [<80041848>] ret_from_irq+0x0/0x4
+ [<80182fdc>] ioread32+0x4/0xc
+ [<81b4c42c>] ath5k_hw_set_sleep_clock+0x2ec/0x474 [ath5k]
+ [<81b4cf28>] ath5k_hw_reset+0x50/0xeb8 [ath5k]
+ [<81b50900>] ath5k_reset+0xd4/0x310 [ath5k]
+ [<81b557e8>] ath5k_config+0x4c/0x104 [ath5k]
+ [<80d01770>] ieee80211_hw_config+0x2f4/0x35c [mac80211]
+ [<80d09aa8>] ieee80211_scan_work+0x2e4/0x414 [mac80211]
+ [<8022c3f4>] process_one_work+0x28c/0x400
+ [<802df8f8>] worker_thread+0x258/0x3c0
+ [<801b5710>] kthread+0xe0/0xec
+ [<800418a8>] ret_from_kernel_thread+0x14/0x1c
+
+The easiest way to reproduce this warning is to run scan with dualband
+NIC in noisy environments, when the channel 11 runs multiple APs. In my
+tests if the APs num >= 12, the warning appears in the first few
+seconds of scanning.
+
+In order to fix this, the Rx disable code moved to a higher level and
+placed before the channel pointer update. This is also makes the code a
+bit more symmetrical, since we disable and enable the Rx in the same
+function.
+
+In fact, at the pointer update time new frames should not appear,
+because interrupt generation at this point should already be disabled.
+The next patch should address this issue.
+
+CC: Jiri Slaby <jirislaby at gmail.com>
+CC: Nick Kossifidis <mickflemm at gmail.com>
+CC: Luis R. Rodriguez <mcgrof at do-not-panic.com>
+Reported-by: Christophe Prevotaux <cprevotaux at nltinc.com>
+Tested-by: Christophe Prevotaux <cprevotaux at nltinc.com>
+Tested-by: Eric Bree <ebree at nltinc.com>
+Signed-off-by: Sergey Ryazanov <ryazanov.s.a at gmail.com>
+---
+ drivers/net/wireless/ath/ath5k/base.c | 24 +++++++++++++++++++++---
+ drivers/net/wireless/ath/ath5k/reset.c | 24 ------------------------
+ 2 files changed, 21 insertions(+), 27 deletions(-)
+
+diff --git a/drivers/net/wireless/ath/ath5k/base.c b/drivers/net/wireless/ath/ath5k/base.c
+index bc9cb35..34b2f15 100644
+--- a/drivers/net/wireless/ath/ath5k/base.c
++++ b/drivers/net/wireless/ath/ath5k/base.c
+@@ -2858,7 +2858,7 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan,
+ {
+ struct ath_common *common = ath5k_hw_common(ah);
+ int ret, ani_mode;
+- bool fast;
++ bool fast = chan && modparam_fastchanswitch ? 1 : 0;
+
+ ATH5K_DBG(ah, ATH5K_DEBUG_RESET, "resetting\n");
+
+@@ -2876,11 +2876,29 @@ ath5k_reset(struct ath5k_hw *ah, struct ieee80211_channel *chan,
+ * so we should also free any remaining
+ * tx buffers */
+ ath5k_drain_tx_buffs(ah);
++
++ /* Stop PCU */
++ ath5k_hw_stop_rx_pcu(ah);
++
++ /* Stop DMA
++ *
++ * Note: If DMA didn't stop continue
++ * since only a reset will fix it.
++ */
++ ret = ath5k_hw_dma_stop(ah);
++
++ /* RF Bus grant won't work if we have pending
++ * frames
++ */
++ if (ret && fast) {
++ ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
++ "DMA didn't stop, falling back to normal reset\n");
++ fast = false;
++ }
++
+ if (chan)
+ ah->curchan = chan;
+
+- fast = ((chan != NULL) && modparam_fastchanswitch) ? 1 : 0;
+-
+ ret = ath5k_hw_reset(ah, ah->opmode, ah->curchan, fast, skip_pcu);
+ if (ret) {
+ ATH5K_ERR(ah, "can't reset hardware (%d)\n", ret);
+diff --git a/drivers/net/wireless/ath/ath5k/reset.c b/drivers/net/wireless/ath/ath5k/reset.c
+index b9b651e..99e62f9 100644
+--- a/drivers/net/wireless/ath/ath5k/reset.c
++++ b/drivers/net/wireless/ath/ath5k/reset.c
+@@ -1169,30 +1169,6 @@ ath5k_hw_reset(struct ath5k_hw *ah, enum nl80211_iftype op_mode,
+ if (ah->ah_version == AR5K_AR5212)
+ ath5k_hw_set_sleep_clock(ah, false);
+
+- /*
+- * Stop PCU
+- */
+- ath5k_hw_stop_rx_pcu(ah);
+-
+- /*
+- * Stop DMA
+- *
+- * Note: If DMA didn't stop continue
+- * since only a reset will fix it.
+- */
+- ret = ath5k_hw_dma_stop(ah);
+-
+- /* RF Bus grant won't work if we have pending
+- * frames */
+- if (ret && fast) {
+- ATH5K_DBG(ah, ATH5K_DEBUG_RESET,
+- "DMA didn't stop, falling back to normal reset\n");
+- fast = false;
+- /* Non fatal, just continue with
+- * normal reset */
+- ret = 0;
+- }
+-
+ mode = channel->hw_value;
+ switch (mode) {
+ case AR5K_MODE_11A:
--
2.0.4
_______________________________________________
openwrt-devel mailing list
openwrt-devel at lists.openwrt.org
https://lists.openwrt.org/cgi-bin/mailman/listinfo/openwrt-devel
More information about the openwrt-devel
mailing list