pull request: iwlwifi-next 2014-1-20

PATCH In review Emmanuel Grumbach 3 participants 4 messages Jan 20, 2014 – Jan 23, 2014 Networking drivers (wireless)

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Emmanuel Grumbach

author

2014-01-20 10:47 UTC #0 lore raw

Hi John,

Well... I know... Not something to be proud of...

A critical bug has been reported on all NICs supported by iwldvm. iwlwifi would simply panic upon interface up This patch fixes this. The offending code is by me and is present in wireless-next.git and hence in net-next.git.
I hope that this pull reuqest can reach 3.14-rc1 otherwise, all the system with NICs supported by iwldvm will simply lock up.

Thanks!

The following changes since commit cf38e4f756d6396657c76f72ef42b6f47c523f97:

iwlwifi: mvm: don't use highest rate in VHT MCS Set (2014-01-13
22:17:22 +0200)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-next.git
for-john

for you to fetch changes up to 23e76d1a516eef416fb5c038791e943fc0916b67:

iwlwifi: pcie: don't panic on host commands in iwldvm (2014-01-20
12:32:06 +0200)

----------------------------------------------------------------
Emmanuel Grumbach (1):
iwlwifi: pcie: don't panic on host commands in iwldvm

 drivers/net/wireless/iwlwifi/pcie/tx.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Emmanuel Grumbach

author

2014-01-20 10:49 UTC #1 lore raw

PATCH 1/1 iwlwifi: pcie: don't panic on host commands in iwldvm

From: Emmanuel Grumbach <[email protected]>

None of the devices supported by iwldvm have support for shadow registers. This means that we wake the NIC when we increment the write pointer on Tx ring. This happened even before my bad commit mentionned below. Since my commit below, we wake up the NIC when we put a host command on the ring regardless of shadow register support. This means that in iwldvm (when the NIC doesn't support shadow register), we wake up the NIC twice:

pcie_enqueue_hcmd:
wake up the NIC iwl_pcie_txq_inc_wr_ptr:
wake up the NIC - no shadow reg support

Since waking up the NIC means that we need to acquire a spinlock, this obviously leads to a recursive spinlock and hence a freeze.

Fixes b9439491055a ("iwlwifi: pcie: keep the NIC awake when commands are in flight")

Reported-by Janusz Dziedzic <[email protected]>

Reviewed-by Johannes Berg <[email protected]>

Signed-off-by Emmanuel Grumbach <[email protected]>

---
 drivers/net/wireless/iwlwifi/pcie/tx.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

drivers/net/wireless/iwlwifi/pcie/tx.c +3 -1

index 3b14fa8..3d54900 100644
@@ -289,13 +289,15 @@ static void iwl_pcie_txq_inval_byte_cnt_tbl(struct iwl_trans *trans,
  */
 void iwl_pcie_txq_inc_wr_ptr(struct iwl_trans *trans, struct iwl_txq *txq)
 {
+	struct iwl_trans_pcie *trans_pcie = IWL_TRANS_GET_PCIE_TRANS(trans);
 	u32 reg = 0;
 	int txq_id = txq->q.id;
 
 	if (txq->need_update == 0)
 		return;
 
-	if (trans->cfg->base_params->shadow_reg_enable) {
+	if (trans->cfg->base_params->shadow_reg_enable ||
+	    txq_id == trans_pcie->cmd_queue) {
 		/* shadow register enabled */
 		iwl_write32(trans, HBUS_TARG_WRPTR,
 			    txq->q.write_ptr | (txq_id << 8));

Signature · 1 line

1.7.9.5

Kalle Valo

Tested-by on v1 1/1

2014-01-23 15:46 UTC #2 lore raw

Re: [PATCH] iwlwifi: pcie: don't panic on host commands in iwldvm

Quoted 16 lines · Emmanuel Grumbach

From: Emmanuel Grumbach <[email protected]>
None of the devices supported by iwldvm have support for shadow registers. This means that we wake the NIC when we increment the write pointer on Tx ring. This happened even before my bad commit mentionned below. Since my commit below, we wake up the NIC when we put a host command on the ring regardless of shadow register support. This means that in iwldvm (when the NIC doesn't support shadow register), we wake up the NIC twice:
pcie_enqueue_hcmd:
wake up the NIC iwl_pcie_txq_inc_wr_ptr:
wake up the NIC - no shadow reg support

Quoted 8 lines

Since waking up the NIC means that we need to acquire a spinlock, this obviously leads to a recursive spinlock and hence a freeze.
Fixes b9439491055a ("iwlwifi: pcie: keep the NIC awake when commands are in flight")
Reported-by Janusz Dziedzic <[email protected]>
Reviewed-by Johannes Berg <[email protected]>
Signed-off-by Emmanuel Grumbach <[email protected]>

Ah, this is why my laptop was hanging during boot with latest wireless-testing? Thanks for fixing this.

FWIW:

Tested-by Kalle Valo <[email protected]>

Signature · 1 line

Kalle Valo

John W. Linville

2014-01-23 19:15 UTC #3 lore raw

In reply to Emmanuel Grumbach

Quoted 29 lines · Emmanuel Grumbach

Hi John,
Well... I know... Not something to be proud of...
A critical bug has been reported on all NICs supported by iwldvm. iwlwifi would simply panic upon interface up This patch fixes this. The offending code is by me and is present in wireless-next.git and hence in net-next.git.
I hope that this pull reuqest can reach 3.14-rc1 otherwise, all the system with NICs supported by iwldvm will simply lock up.
Thanks!
The following changes since commit cf38e4f756d6396657c76f72ef42b6f47c523f97:
iwlwifi: mvm: don't use highest rate in VHT MCS Set (2014-01-13
22:17:22 +0200)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/iwlwifi/iwlwifi-next.git
for-john
for you to fetch changes up to 23e76d1a516eef416fb5c038791e943fc0916b67:
iwlwifi: pcie: don't panic on host commands in iwldvm (2014-01-20
12:32:06 +0200)

Quoted 6 lines

----------------------------------------------------------------
Emmanuel Grumbach (1):
iwlwifi: pcie: don't panic on host commands in iwldvm
 drivers/net/wireless/iwlwifi/pcie/tx.c |    4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Pulling now...

Signature · 2 lines

John W. Linville		Someday the world will need a hero, and you
[email protected]			might be all we have.  Be ready.