[ 19/42] iwlwifi: disable the buggy chain extension feature in HW
From: Greg KH <gregkh@linuxfoundation.org>
Date: 2012-06-14 23:59:53
Also in:
lkml
3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Emmanuel Grumbach <redacted> 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 <redacted> Signed-off-by: Johannes Berg <redacted> Signed-off-by: John W. Linville <redacted> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- drivers/net/wireless/iwlwifi/iwl-prph.h | 1 + drivers/net/wireless/iwlwifi/iwl-trans-pcie.c | 5 +++++ 2 files changed, 6 insertions(+)
--- 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) --- a/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c +++ b/drivers/net/wireless/iwlwifi/iwl-trans-pcie.c
@@ -1128,6 +1128,11 @@ static void iwl_tx_start(struct iwl_tran 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),