iwlwifi: disable the buggy chain extension feature in HW
commit d012d04e4d6312ea157b6cf19e9689af934f5aa7 upstream.
This feature has been reported to be buggy and enabled by
default. We therefore need to disable it manually.
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/net/wireless/iwlwifi/iwl-prph.h b/drivers/net/wireless/iwlwifi/iwl-prph.h
index 3b10692..dfd5466 100644
--- a/drivers/net/wireless/iwlwifi/iwl-prph.h
+++ b/drivers/net/wireless/iwlwifi/iwl-prph.h
@@ -224,6 +224,7 @@
#define SCD_TXFACT (SCD_BASE + 0x10)
#define SCD_ACTIVE (SCD_BASE + 0x14)
#define SCD_QUEUECHAIN_SEL (SCD_BASE + 0xe8)
+#define SCD_CHAINEXT_EN (SCD_BASE + 0x244)
#define SCD_AGGR_SEL (SCD_BASE + 0x248)
#define SCD_INTERRUPT_MASK (SCD_BASE + 0x108)
diff --git a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c
index 4d7b30d..66df016 100644
--- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c
+++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c
@@ -1128,6 +1128,11 @@
iwl_write_prph(trans, SCD_DRAM_BASE_ADDR,
trans_pcie->scd_bc_tbls.dma >> 10);
+ /* The chain extension of the SCD doesn't work well. This feature is
+ * enabled by default by the HW, so we need to disable it manually.
+ */
+ iwl_write_prph(trans, SCD_CHAINEXT_EN, 0);
+
/* Enable DMA channel */
for (chan = 0; chan < FH_TCSR_CHNL_NUM ; chan++)
iwl_write_direct32(trans, FH_TCSR_CHNL_TX_CONFIG_REG(chan),