I'm using RingIO for transmitting large amounts of data between ARM and DSP. Everything goes well, except from one thing. RingIO_sendNotify called from Linux to DSP tends to block once a few calls. Under what circumstances does RingIO_sendNotify block? Sending notifications from DSP to Linux seems to work just fine.
Kernel spits out:
Pid: 737, comm: ringio
CPU: 0 Tainted: P (2.6.31-rc7-davinci1 #87)
PC is at IPS_notify+0xcc/0x1ac [dsplinkk]
LR is at __mutex_unlock_slowpath+0x104/0x118
pc : [<bf05d50c>] lr : [<c029a820>] psr: 20000013
sp : c1f2fe50 ip : c1f2fe14 fp : c1f2fe8c
r10: 00000000 r9 : c2aa9180 r8 : 00000000
r7 : 01122b54 r6 : c2aa8000 r5 : 00008000 r4 : bf077610
r3 : 00000001 r2 : 02faf080 r1 : 00000000 r0 : c2abd000
Flags: nzCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 0005317f Table: c1f18000 DAC: 00000015
[<c002bee8>] (show_regs+0x0/0x4c) from [<c006c5f0>] (softlockup_tick+0x114/0x184)
r4:0000001f
[<c006c4dc>] (softlockup_tick+0x0/0x184) from [<c0049da0>] (run_local_timers+0x1c/0x20)
[<c0049d84>] (run_local_timers+0x0/0x20) from [<c004a09c>] (update_process_times+0x34/0x64)
[<c004a068>] (update_process_times+0x0/0x64) from [<c0062884>] (tick_sched_timer+0x94/0xcc)
r6:00000062 r5:2f16bc7c r4:c035ffd4
[<c00627f0>] (tick_sched_timer+0x0/0xcc) from [<c005981c>] (__run_hrtimer+0x9c/0xf4)
r7:ffffffff r6:c035fac0 r5:c035ffd4 r4:c00627f0
[<c0059780>] (__run_hrtimer+0x0/0xf4) from [<c0059be0>] (hrtimer_interrupt+0x1c0/0x260)
r6:00000062 r5:2f16a72a r4:00000000
[<c0059a20>] (hrtimer_interrupt+0x0/0x260) from [<c0033b80>] (timer_interrupt+0x1c/0x28)
[<c0033b64>] (timer_interrupt+0x0/0x28) from [<c006cb10>] (handle_IRQ_event+0x44/0x110)
[<c006cacc>] (handle_IRQ_event+0x0/0x110) from [<c006f054>] (handle_edge_irq+0x148/0x1b0)
r7:c035ab3c r6:00000015 r5:c0360930 r4:c1f2e000
[<c006ef0c>] (handle_edge_irq+0x0/0x1b0) from [<c002a070>] (_text+0x70/0x8c)
r7:00000002 r6:00200000 r5:00000000 r4:00000015
[<c002a000>] (_text+0x0/0x8c) from [<c002aa60>] (__irq_svc+0x40/0x90)
Exception stack(0xc1f2fe08 to 0xc1f2fe50)
fe00: c2abd000 00000000 02faf080 00000001 bf077610 00008000
fe20: c2aa8000 01122b54 00000000 c2aa9180 00000000 c1f2fe8c c1f2fe14 c1f2fe50
fe40: c029a820 bf05d50c 20000013 ffffffff
r5:febfd000 r4:ffffffff
[<bf05d440>] (IPS_notify+0x0/0x1ac [dsplinkk]) from [<bf06aa5c>] (NOTIFY_KnlNotify+0x30/0x44 [dsplinkk])
[<bf06aa2c>] (NOTIFY_KnlNotify+0x0/0x44 [dsplinkk]) from [<bf06d7f0>] (DRV_Ioctl+0x7d0/0x974 [dsplinkk])
[<bf06d020>] (DRV_Ioctl+0x0/0x974 [dsplinkk]) from [<c00a65c4>] (vfs_ioctl+0x78/0x94)
r7:00000003 r6:be81356c r5:00007305 r4:c1ea5b80
[<c00a654c>] (vfs_ioctl+0x0/0x94) from [<c00a721c>] (do_vfs_ioctl+0x578/0x5d0)
r6:be81356c r5:c182e0f4 r4:c1ea5b80
[<c00a6ca4>] (do_vfs_ioctl+0x0/0x5d0) from [<c00a72b4>] (sys_ioctl+0x40/0x60)
r8:c002b004 r7:00000036 r6:00007305 r5:fffffff7 r4:c1ea5b80
[<c00a7274>] (sys_ioctl+0x0/0x60) from [<c002ae60>] (ret_fast_syscall+0x0/0x2c)
r6:00008c2c r5:00008c20 r4:be815ec4
BUG: soft lockup - CPU#0 stuck for 61s! [ringio:737]
Modules linked in: texas(P) dsplinkk g_serial kmod_pbx dspdet(P)
Pid: 737, comm: ringio
CPU: 0 Tainted: P (2.6.31-rc7-davinci1 #87)
PC is at __mutex_lock_interruptible_slowpath+0x288/0x2e4
LR is at __mutex_lock_interruptible_slowpath+0x26c/0x2e4
pc : [<c029ae90>] lr : [<c029ae74>] psr: 60000013
sp : c1f2fdf8 ip : c1f2fdf8 fp : c1f2fe28
r10: 00000000 r9 : c2aa9180 r8 : c1eb6fa0
r7 : 0242df2e r6 : c2abd000 r5 : 60000013 r4 : c1f2e000
r3 : 00000000 r2 : c2abd004 r1 : 00000000 r0 : c2abd000
Flags: nZCv IRQs on FIQs on Mode SVC_32 ISA ARM Segment user
Control: 0005317f Table: c1f18000 DAC: 00000015
[<c002bee8>] (show_regs+0x0/0x4c) from [<c006c5f0>] (softlockup_tick+0x114/0x184)
r4:0000005c
[<c006c4dc>] (softlockup_tick+0x0/0x184) from [<c0049da0>] (run_local_timers+0x1c/0x20)
[<c0049d84>] (run_local_timers+0x0/0x20) from [<c004a09c>] (update_process_times+0x34/0x64)
[<c004a068>] (update_process_times+0x0/0x64) from [<c0062884>] (tick_sched_timer+0x94/0xcc)
r6:000000a4 r5:114952c4 r4:c035ffd4
[<c00627f0>] (tick_sched_timer+0x0/0xcc) from [<c005981c>] (__run_hrtimer+0x9c/0xf4)
r7:ffffffff r6:c035fac0 r5:c035ffd4 r4:c00627f0
[<c0059780>] (__run_hrtimer+0x0/0xf4) from [<c0059be0>] (hrtimer_interrupt+0x1c0/0x260)
r6:000000a4 r5:11493fe2 r4:c035aad0
[<c0059a20>] (hrtimer_interrupt+0x0/0x260) from [<c0033b80>] (timer_interrupt+0x1c/0x28)
[<c0033b64>] (timer_interrupt+0x0/0x28) from [<c006cb10>] (handle_IRQ_event+0x44/0x110)
[<c006cacc>] (handle_IRQ_event+0x0/0x110) from [<c006f054>] (handle_edge_irq+0x148/0x1b0)
r7:c035ab3c r6:00000015 r5:c0360930 r4:c1f2e000
[<c006ef0c>] (handle_edge_irq+0x0/0x1b0) from [<c002a070>] (_text+0x70/0x8c)
r7:00000003 r6:00200000 r5:00000000 r4:00000015
[<c002a000>] (_text+0x0/0x8c) from [<c002aa60>] (__irq_svc+0x40/0x90)
Exception stack(0xc1f2fdb0 to 0xc1f2fdf8)
fda0: c2abd000 00000000 c2abd004 00000000
fdc0: c1f2e000 60000013 c2abd000 0242df2e c1eb6fa0 c2aa9180 00000000 c1f2fe28
fde0: c1f2fdf8 c1f2fdf8 c029ae74 c029ae90 60000013 ffffffff
r5:febfd000 r4:ffffffff
[<c029ac08>] (__mutex_lock_interruptible_slowpath+0x0/0x2e4) from [<c029af00>] (mutex_lock_interruptible+0x14/0x28)
r8:00000000 r7:0242df2e r6:c2aa8000 r5:00008000 r4:c2abd000
[<c029aeec>] (mutex_lock_interruptible+0x0/0x28) from [<bf069a7c>] (SYNC_SpinLockStartEx+0x18/0x24 [dsplinkk])
r4:bf077610
[<bf069a64>] (SYNC_SpinLockStartEx+0x0/0x24 [dsplinkk]) from [<bf05d534>] (IPS_notify+0xf4/0x1ac [dsplinkk])
[<bf05d440>] (IPS_notify+0x0/0x1ac [dsplinkk]) from [<bf06aa5c>] (NOTIFY_KnlNotify+0x30/0x44 [dsplinkk])
[<bf06aa2c>] (NOTIFY_KnlNotify+0x0/0x44 [dsplinkk]) from [<bf06d7f0>] (DRV_Ioctl+0x7d0/0x974 [dsplinkk])
[<bf06d020>] (DRV_Ioctl+0x0/0x974 [dsplinkk]) from [<c00a65c4>] (vfs_ioctl+0x78/0x94)
r7:00000003 r6:be81356c r5:00007305 r4:c1ea5b80
[<c00a654c>] (vfs_ioctl+0x0/0x94) from [<c00a721c>] (do_vfs_ioctl+0x578/0x5d0)
r6:be81356c r5:c182e0f4 r4:c1ea5b80
[<c00a6ca4>] (do_vfs_ioctl+0x0/0x5d0) from [<c00a72b4>] (sys_ioctl+0x40/0x60)
r8:c002b004 r7:00000036 r6:00007305 r5:fffffff7 r4:c1ea5b80
[<c00a7274>] (sys_ioctl+0x0/0x60) from [<c002ae60>] (ret_fast_syscall+0x0/0x2c)
r6:00008c2c r5:00008c20 r4:be815ec4
