[RFC] mwifiex: block work queue while suspended

[James Cameron <quozl@laptop.org>]

The work queue may execute after the device is suspended, leading to
SDIO register I/O over a suspend and resume of the system.  With a
WARN_ON in mwifiex_write_data_to_card we see:

[ 2115.351137] PM: suspend of devices complete after 15.989 msecs
[ 2115.366047] mwifiex_sdio mmc0:0001:1: mwifiex_write_data_sync: not allowed while suspended
[ 2115.366067] mwifiex_sdio mmc0:0001:1: host_to_card, write iomem (1) failed: -1
[ 2115.386023] PM: late suspend of devices complete after 34.845 msecs
[ 2115.386303] PM: noirq suspend of devices complete after 0.272 msecs
[ 2115.386388] before suspend
[ 2115.387824] after resume
[ 2115.388618] PM: noirq resume of devices complete after 0.745 msecs
[ 2115.407641] PM: early resume of devices complete after 18.849 msecs
[ 2125.397532] mmc0: Timeout waiting for hardware interrupt.
[ 2125.397559] mwifiex_sdio mmc0:0001:1: write CFG reg failed
[ 2125.397575] ------------[ cut here ]------------
[ 2125.397575] WARNING: at drivers/net/wireless/mwifiex/sdio.c:485 mwifiex_write_data_to_card+0x98/0xc4 [mwifiex_sdio]()
[ 2125.397746] [<bf0eb34c>] (mwifiex_host_to_card_mp_aggr+0x354/0x46c [mwifiex_sdio])
[ 2125.397746] [<bf0eb5f4>] (mwifiex_sdio_host_to_card+0x190/0x234 [mwifiex_sdio])
[ 2125.397788] [<bf0bed00>] (mwifiex_process_tx+0x90/0x1a0 [mwifiex])
[ 2125.397823] [<bf0bf8a0>] (mwifiex_send_single_packet+0x134/0x2b0 [mwifiex])
[ 2125.397857] [<bf0c074c>] (mwifiex_wmm_process_tx+0x76c/0x800 [mwifiex])
[ 2125.397887] [<bf0ba3f8>] (mwifiex_main_process+0x344/0x504 [mwifiex])
[ 2125.397913] [<bf0ba5e0>] (mwifiex_main_work_queue+0x28/0x2c [mwifiex])
[ 2125.397949] [<c00409fc>] (process_one_work+0x260/0x488)
[ 2125.397949] [<c0040e40>] (worker_thread+0x1e0/0x32c)
[ 2125.397979] [<c00464d0>] (kthread+0x9c/0xac)
[ 2125.397979] ---[ end trace 86d7b628a6c8ddd0 ]---
---

Test environment is an OLPC XO-4 doing one sleep every few seconds,
with the device configured to wake the system, with constant ping by
another host.  Kernel is 3.5 with many backported mwifiex patches.

We also see that an SDIO interrupt from the device may occur after all
devices are suspended, leading to a similar symptom:

[ 1292.887221] PM: suspend of devices complete after 21.990 msecs
[ 1292.922632] PM: late suspend of devices complete after 35.403 msecs
[ 1292.922901] PM: noirq suspend of devices complete after 0.001 msecs
               <-- here an mmc register read begins in sdio_irq_thread
[ 1292.923020] before suspend
[ 1292.953311] after resume
[ 1292.954106] PM: noirq resume of devices complete after 0.099 msecs
[ 1292.973124] PM: early resume of devices complete after 18.814 msecs
[ 1302.923009] mmc0: Timeout waiting for hardware interrupt.
[ 1302.923050] ------------[ cut here ]------------
[ 1302.923075] WARNING: at drivers/net/wireless/mwifiex/sdio.c:688 mwifiex_sdio_interrupt+0xcc/0x21c [mwifiex_sdio]()
[ 1302.923204] [<bf0c089c>] (mwifiex_sdio_interrupt+0xcc/0x21c [mwifiex_sdio])
[ 1302.923218] [<c0302be4>] (sdio_irq_thread+0x178/0x2f0)
[ 1302.923218] [<c00464d0>] (kthread+0x9c/0xac)
[ 1302.923235] ---[ end trace 7e9f40af36cc200c ]---
[ 1302.923240] mwifiex_sdio mmc0:0001:1: read mp_regs failed, will retry ...
[ 1302.923291] mwifiex_sdio mmc0:0001:1: read mp_regs worked on retry
[ 1303.554228] PM: resume of devices complete after 10581.100 msecs
               ^-- note how resume was delayed by mmc0 timeout
[ 1303.745395] Restarting tasks ... done.
[ 1312.943035] mwifiex_sdio mmc0:0001:1: mwifiex_cmd_timeout_func: Timeout cmd id (1400141716.779991) = 0xe5, act = 0x1

I don't know how to fix this one yet; I don't know why the SDHCI
transaction fails, given the clocks remain running.

 drivers/net/wireless/mwifiex/main.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/wireless/mwifiex/main.c b/drivers/net/wireless/mwifiex/main.c
index 9c771b3..512ccd6 100644
--- a/drivers/net/wireless/mwifiex/main.c
+++ b/drivers/net/wireless/mwifiex/main.c
@@ -833,6 +833,8 @@ static void mwifiex_main_work_queue(struct work_struct *work)
 
 	if (adapter->surprise_removed)
 		return;
+	if (adapter->is_suspended)
+		return;
 	mwifiex_main_process(adapter);
 }
 
-- 
1.9.1


-- 
James Cameron
http://quozl.linux.org.au/