From d012d04e4d6312ea157b6cf19e9689af934f5aa7 Mon Sep 17 00:00:00 2001 From: Emmanuel Grumbach Date: Wed, 6 Jun 2012 13:55:02 +0200 Subject: [PATCH] iwlwifi: disable the buggy chain extension feature in HW This feature has been reported to be buggy and enabled by default. We therefore need to disable it manually. Cc: stable@vger.kernel.org Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg Signed-off-by: John W. Linville --- drivers/net/wireless/iwlwifi/iwl-prph.h | 1 + drivers/net/wireless/iwlwifi/iwl-trans-pcie.c | 5 +++++ 2 files changed, 6 insertions(+), 0 deletions(-) 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 ec6fb39..79c6b91 100644 --- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c +++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c @@ -1058,6 +1058,11 @@ static void iwl_tx_start(struct iwl_trans *trans) 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), -- 1.7.7.6