Re: [PATCH v4 0/7] add virt-dma support for imx-sdma

[Robin Gong]

Hi Lucas,
	Could you double check again? Still can reproduce lockdep
warning on UART if change
spin_lock_lockirqsave/spinlock_unlock_irqrestore to
spin_lock/spin_unlock in sdma_int_handler as you said without patch7/7.
Would you please ask below two more questions?
1. Does your uart case pass now with my v4 patchset?
2. Do you make some code change in your local('I just gave this series
a spin')to reproduce your below issue? If yes, could you post your
change?

On å, 2018-06-14 at 10:53 +0200, Lucas Stach wrote:
> Hi Robin,
> 
> I just gave this series a spin and it seems there is even more
> locking
> fun, see the lockdep output below. After taking a short look it seems
> this is caused by using the wrong spinlock variants in
> sdma_int_handler(), those should also use the _irqsave ones. When
> fixing this you might want to reconsider patch 7/7, as it's probably
> not needed at all.
> 
> Regards,
> Lucas
> 
> [ÂÂÂ20.479401]
> ========================================================
> [ÂÂÂ20.485769] WARNING: possible irq lock inversion dependency
> detected
> [ÂÂÂ20.492140] 4.17.0+ #1538 Not tainted
> [ÂÂÂ20.495814] ------------------------------------------------------
> --
> [ÂÂÂ20.502181] systemd/1 just changed the state of lock:
> [ÂÂÂ20.507247] c0abdafc (&(&substream->self_group.lock)->rlock){-
> ...}, at: snd_pcm_stream_lock+0x54/0x60
> [ÂÂÂ20.516523] but this lock took another, HARDIRQ-unsafe lock in the
> past:
> [ÂÂÂ20.523234]ÂÂ(fs_reclaim){+.+.}
> [ÂÂÂ20.523253]Â
> [ÂÂÂ20.523253]Â
> [ÂÂÂ20.523253] and interrupts could create inverse lock ordering
> between them.
> [ÂÂÂ20.523253]Â
> [ÂÂÂ20.537804]Â
> [ÂÂÂ20.537804] other info that might help us debug this:
> [ÂÂÂ20.544344]ÂÂPossible interrupt unsafe locking scenario:
> [ÂÂÂ20.544344]Â
> [ÂÂÂ20.551144]ÂÂÂÂÂÂÂÂCPU0ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂCPU1
> [ÂÂÂ20.555686]ÂÂÂÂÂÂÂÂ----ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ----
> [ÂÂÂ20.560224]ÂÂÂlock(fs_reclaim);
> [ÂÂÂ20.563386]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlocal_irq_disable();
> [ÂÂÂ20.569315]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock(&(&substream-
> >self_group.lock)->rlock);
> [ÂÂÂ20.577337]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock(fs_reclaim);
> [ÂÂÂ20.583014]ÂÂÂ<Interrupt>
> [ÂÂÂ20.585643]ÂÂÂÂÂlock(&(&substream->self_group.lock)->rlock);
> [ÂÂÂ20.591322]Â
> [ÂÂÂ20.591322]ÂÂ*** DEADLOCK ***
> [ÂÂÂ20.591322]Â
> [ÂÂÂ20.597260] 1 lock held by systemd/1:
> [ÂÂÂ20.607806]ÂÂ#0: ab23d11c (snd_pcm_link_rwlock){.-..}, at:
> snd_pcm_stream_lock+0x4c/0x60
> [ÂÂÂ20.615951]Â
> [ÂÂÂ20.615951] the shortest dependencies between 2nd lock and 1st
> lock:
> [ÂÂÂ20.623799]ÂÂ-> (fs_reclaim){+.+.} ops: 248474 {
> [ÂÂÂ20.628456]ÂÂÂÂÂHARDIRQ-ON-W at:
> [ÂÂÂ20.631716]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ20.637223]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂfs_reclaim_acquire+0x48/0x58
> [ÂÂÂ20.643075]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkmem_cache_alloc_trace+0x3c/0x36
> 4
> [ÂÂÂ20.649366]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂalloc_worker.constprop.15+0x28/0
> x64
> [ÂÂÂ20.655824]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂinit_rescuer.part.5+0x20/0xa4
> [ÂÂÂ20.661764]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂworkqueue_init+0x124/0x1f8
> [ÂÂÂ20.667446]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init_freeable+0x60/0x550
> [ÂÂÂ20.673561]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init+0x18/0x120
> [ÂÂÂ20.678890]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂret_from_fork+0x14/0x20
> [ÂÂÂ20.684299]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ(null)
> [ÂÂÂ20.688408]ÂÂÂÂÂSOFTIRQ-ON-W at:
> [ÂÂÂ20.691659]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ20.697158]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂfs_reclaim_acquire+0x48/0x58
> [ÂÂÂ20.703006]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkmem_cache_alloc_trace+0x3c/0x36
> 4
> [ÂÂÂ20.709288]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂalloc_worker.constprop.15+0x28/0
> x64
> [ÂÂÂ20.709301]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂinit_rescuer.part.5+0x20/0xa4
> [ÂÂÂ20.720717]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂworkqueue_init+0x124/0x1f8
> [ÂÂÂ20.720729]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init_freeable+0x60/0x550
> [ÂÂÂ20.720738]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init+0x18/0x120
> [ÂÂÂ20.720746]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂret_from_fork+0x14/0x20
> [ÂÂÂ20.720751]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ(null)
> [ÂÂÂ20.720756]ÂÂÂÂÂINITIAL USE at:
> [ÂÂÂ20.720770]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ20.720782]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂfs_reclaim_acquire+0x48/0x58
> [ÂÂÂ20.774374]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkmem_cache_alloc_trace+0x3c/0x364
> [ÂÂÂ20.780574]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂalloc_worker.constprop.15+0x28/0x
> 64
> [ÂÂÂ20.786945]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂinit_rescuer.part.5+0x20/0xa4
> [ÂÂÂ20.792794]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂworkqueue_init+0x124/0x1f8
> [ÂÂÂ20.798384]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init_freeable+0x60/0x550
> [ÂÂÂ20.804406]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂkernel_init+0x18/0x120
> [ÂÂÂ20.809648]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂret_from_fork+0x14/0x20
> [ÂÂÂ20.814971]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ(null)
> [ÂÂÂ20.818992]ÂÂÂ}
> [ÂÂÂ20.820768]ÂÂÂ... keyÂÂÂÂÂÂat: [<80e22074>]
> __fs_reclaim_map+0x0/0x10
> [ÂÂÂ20.827220]ÂÂÂ... acquired at:
> [ÂÂÂ20.830289]ÂÂÂÂfs_reclaim_acquire+0x48/0x58
> [ÂÂÂ20.834487]ÂÂÂÂkmem_cache_alloc_trace+0x3c/0x364
> [ÂÂÂ20.839123]ÂÂÂÂsdma_transfer_init+0x44/0x130
> [ÂÂÂ20.843409]ÂÂÂÂsdma_prep_dma_cyclic+0x78/0x21c
> [ÂÂÂ20.847869]ÂÂÂÂsnd_dmaengine_pcm_trigger+0xdc/0x184
> [ÂÂÂ20.852764]ÂÂÂÂsoc_pcm_trigger+0x164/0x190
> [ÂÂÂ20.856876]ÂÂÂÂsnd_pcm_do_start+0x34/0x40
> [ÂÂÂ20.860902]ÂÂÂÂsnd_pcm_action_single+0x48/0x74
> [ÂÂÂ20.865360]ÂÂÂÂsnd_pcm_action+0x34/0xfc
> [ÂÂÂ20.869213]ÂÂÂÂsnd_pcm_ioctl+0x910/0x10ec
> [ÂÂÂ20.873241]ÂÂÂÂvfs_ioctl+0x30/0x44
> [ÂÂÂ20.876657]ÂÂÂÂdo_vfs_ioctl+0xac/0x974
> [ÂÂÂ20.880421]ÂÂÂÂksys_ioctl+0x48/0x64
> [ÂÂÂ20.883923]ÂÂÂÂsys_ioctl+0x18/0x1c
> [ÂÂÂ20.887340]ÂÂÂÂret_fast_syscall+0x0/0x28
> [ÂÂÂ20.891277]ÂÂÂÂ0x7289bcbc
> [ÂÂÂ20.893909]Â
> [ÂÂÂ20.895410] -> (&(&substream->self_group.lock)->rlock){-...} ops:
> 59 {
> [ÂÂÂ20.901977]ÂÂÂÂIN-HARDIRQ-W at:
> [ÂÂÂ20.905143]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ20.910473]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ_raw_spin_lock+0x48/0x58
> [ÂÂÂ20.915801]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_stream_lock+0x54/0x60
> [ÂÂÂ20.921561]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ_snd_pcm_stream_lock_irqsave+0x40/
> 0x48
> [ÂÂÂ20.928107]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_period_elapsed+0x2c/0xa4
> [ÂÂÂ20.934127]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂdmaengine_pcm_dma_complete+0x54/0x
> 58
> [ÂÂÂ20.940498]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsdma_int_handler+0x1dc/0x2a8
> [ÂÂÂ20.946179]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ__handle_irq_event_percpu+0x1fc/0x
> 498
> [ÂÂÂ20.952635]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂhandle_irq_event_percpu+0x38/0x8c
> [ÂÂÂ20.958742]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂhandle_irq_event+0x48/0x6c
> [ÂÂÂ20.964242]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂhandle_fasteoi_irq+0xc4/0x138
> [ÂÂÂ20.970006]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂgeneric_handle_irq+0x28/0x38
> [ÂÂÂ20.975681]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ__handle_domain_irq+0xb0/0xc4
> [ÂÂÂ20.981443]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂgic_handle_irq+0x68/0xa0
> [ÂÂÂ20.986769]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ__irq_svc+0x70/0xb0
> [ÂÂÂ20.991662]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ_raw_spin_unlock_irq+0x38/0x6c
> [ÂÂÂ20.997511]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂtask_work_run+0x90/0xb8
> [ÂÂÂ21.002751]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂdo_work_pending+0xc8/0xd0
> [ÂÂÂ21.008164]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂslow_work_pending+0xc/0x20
> [ÂÂÂ21.013661]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x76c77e86
> [ÂÂÂ21.017768]ÂÂÂÂINITIAL USE at:
> [ÂÂÂ21.020844]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ21.026086]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ_raw_spin_lock+0x48/0x58
> [ÂÂÂ21.031328]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_stream_lock+0x54/0x60
> [ÂÂÂ21.037002]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_stream_lock_irq+0x38/0x3c
> [ÂÂÂ21.043023]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_sync_ptr+0x214/0x260
> [ÂÂÂ21.048609]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsnd_pcm_ioctl+0xbe0/0x10ec
> [ÂÂÂ21.054027]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂvfs_ioctl+0x30/0x44
> [ÂÂÂ21.058832]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂdo_vfs_ioctl+0xac/0x974
> [ÂÂÂ21.063984]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂksys_ioctl+0x48/0x64
> [ÂÂÂ21.068875]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂsys_ioctl+0x18/0x1c
> [ÂÂÂ21.073679]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂret_fast_syscall+0x0/0x28
> [ÂÂÂ21.079004]ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ0x7e9026dc
> [ÂÂÂ21.083023]ÂÂ}
> [ÂÂÂ21.084710]ÂÂ... keyÂÂÂÂÂÂat: [<8162a6e4>] __key.31798+0x0/0x8
> [ÂÂÂ21.090552]ÂÂ... acquired at:
> [ÂÂÂ21.093537]ÂÂÂÂmark_lock+0x3a4/0x69c
> [ÂÂÂ21.097128]ÂÂÂÂ__lock_acquire+0x420/0x16d4
> [ÂÂÂ21.101239]ÂÂÂÂlock_acquire+0x260/0x29c
> [ÂÂÂ21.105091]ÂÂÂÂ_raw_spin_lock+0x48/0x58
> [ÂÂÂ21.108940]ÂÂÂÂsnd_pcm_stream_lock+0x54/0x60
> [ÂÂÂ21.113226]ÂÂÂÂ_snd_pcm_stream_lock_irqsave+0x40/0x48
> [ÂÂÂ21.118296]ÂÂÂÂsnd_pcm_period_elapsed+0x2c/0xa4
> [ÂÂÂ21.122841]ÂÂÂÂdmaengine_pcm_dma_complete+0x54/0x58
> [ÂÂÂ21.127735]ÂÂÂÂsdma_int_handler+0x1dc/0x2a8
> [ÂÂÂ21.131937]ÂÂÂÂ__handle_irq_event_percpu+0x1fc/0x498
> [ÂÂÂ21.136915]ÂÂÂÂhandle_irq_event_percpu+0x38/0x8c
> [ÂÂÂ21.141547]ÂÂÂÂhandle_irq_event+0x48/0x6c
> [ÂÂÂ21.145570]ÂÂÂÂhandle_fasteoi_irq+0xc4/0x138
> [ÂÂÂ21.149854]ÂÂÂÂgeneric_handle_irq+0x28/0x38
> [ÂÂÂ21.154052]ÂÂÂÂ__handle_domain_irq+0xb0/0xc4
> [ÂÂÂ21.158335]ÂÂÂÂgic_handle_irq+0x68/0xa0
> [ÂÂÂ21.162184]ÂÂÂÂ__irq_svc+0x70/0xb0
> [ÂÂÂ21.165601]ÂÂÂÂ_raw_spin_unlock_irq+0x38/0x6c
> [ÂÂÂ21.169973]ÂÂÂÂtask_work_run+0x90/0xb8
> [ÂÂÂ21.173735]ÂÂÂÂdo_work_pending+0xc8/0xd0
> [ÂÂÂ21.177670]ÂÂÂÂslow_work_pending+0xc/0x20
> [ÂÂÂ21.181691]ÂÂÂÂ0x76c77e86
> [ÂÂÂ21.184320]Â
> [ÂÂÂ21.185821]Â
> [ÂÂÂ21.185821] stack backtrace:
> [ÂÂÂ21.190198] CPU: 0 PID: 1 Comm: systemd Not tainted 4.17.0+ #1538
> [ÂÂÂ21.196303] Hardware name: Freescale i.MX6 Quad/DualLite (Device
> Tree)
> [ÂÂÂ21.202841] Backtrace:Â
> [ÂÂÂ21.205314] [<8010e318>] (dump_backtrace) from [<8010e604>]
> (show_stack+0x20/0x24)
> [ÂÂÂ21.212900]ÂÂr7:80e9f3d0 r6:00000000 r5:60070193 r4:80e9f3d0
> [ÂÂÂ21.218581] [<8010e5e4>] (show_stack) from [<8099b660>]
> (dump_stack+0xa4/0xd8)
> [ÂÂÂ21.225825] [<8099b5bc>] (dump_stack) from [<8017b52c>]
> (print_irq_inversion_bug+0x15c/0x1fc)
> [ÂÂÂ21.234368]ÂÂr9:814da818 r8:00000001 r7:ee926c00 r6:00000000
> r5:ee915bb0 r4:814da818
> [ÂÂÂ21.242133] [<8017b3d0>] (print_irq_inversion_bug) from
> [<8017b6dc>] (check_usage_forwards+0x110/0x13c)
> [ÂÂÂ21.251544]ÂÂr9:00000002 r8:80bfd3e2 r7:ee926c00 r6:ee927148
> r5:80e08488 r4:00000001
> [ÂÂÂ21.259306] [<8017b5cc>] (check_usage_forwards) from [<8017c2a4>]
> (mark_lock+0x3a4/0x69c)
> [ÂÂÂ21.267500]ÂÂr9:ee926c00 r8:80a03cd8 r7:00000101 r6:00000002
> r5:00000000 r4:ee927148
> [ÂÂÂ21.275263] [<8017bf00>] (mark_lock) from [<8017cf68>]
> (__lock_acquire+0x420/0x16d4)
> [ÂÂÂ21.283023]ÂÂr10:ee927148 r9:ed4620e4 r8:ee926c00 r7:00000000
> r6:00000001 r5:00000001
> [ÂÂÂ21.290863]ÂÂr4:00000490
> [ÂÂÂ21.293416] [<8017cb48>] (__lock_acquire) from [<8017ed58>]
> (lock_acquire+0x260/0x29c)
> [ÂÂÂ21.301350]ÂÂr10:00000001 r9:80e084a4 r8:00000000 r7:00000000
> r6:00000000 r5:ed4620e4
> [ÂÂÂ21.309189]ÂÂr4:00000000
> [ÂÂÂ21.311746] [<8017eaf8>] (lock_acquire) from [<809b74f0>]
> (_raw_spin_lock+0x48/0x58)
> [ÂÂÂ21.319506]ÂÂr10:ee0a4714 r9:ed457100 r8:ee0a46c8 r7:ee0a4714
> r6:ee0a4010 r5:807847b0
> [ÂÂÂ21.327346]ÂÂr4:ed4620d4
> [ÂÂÂ21.329902] [<809b74a8>] (_raw_spin_lock) from [<807847b0>]
> (snd_pcm_stream_lock+0x54/0x60)
> [ÂÂÂ21.338265]ÂÂr5:ed462000 r4:ed462000
> [ÂÂÂ21.341863] [<8078475c>] (snd_pcm_stream_lock) from [<80784838>]
> (_snd_pcm_stream_lock_irqsave+0x40/0x48)
> [ÂÂÂ21.351440]ÂÂr5:ed462000 r4:60070193
> [ÂÂÂ21.355042] [<807847f8>] (_snd_pcm_stream_lock_irqsave) from
> [<8078b044>] (snd_pcm_period_elapsed+0x2c/0xa4)
> [ÂÂÂ21.364881]ÂÂr5:ee3ef000 r4:ed462000
> [ÂÂÂ21.368478] [<8078b018>] (snd_pcm_period_elapsed) from
> [<8078d7b4>] (dmaengine_pcm_dma_complete+0x54/0x58)
> [ÂÂÂ21.378148]ÂÂr7:ee0a4714 r6:ee0a4010 r5:00000007 r4:ee0a46bc
> [ÂÂÂ21.383827] [<8078d760>] (dmaengine_pcm_dma_complete) from
> [<80504c0c>] (sdma_int_handler+0x1dc/0x2a8)
> [ÂÂÂ21.393157] [<80504a30>] (sdma_int_handler) from [<8018cd28>]
> (__handle_irq_event_percpu+0x1fc/0x498)
> [ÂÂÂ21.402393]ÂÂr10:00000000 r9:eeafd400 r8:80e084a4 r7:00000038
> r6:00000038 r5:80ea3c12
> [ÂÂÂ21.410233]ÂÂr4:ee2b5d40
> [ÂÂÂ21.412787] [<8018cb2c>] (__handle_irq_event_percpu) from
> [<8018cffc>] (handle_irq_event_percpu+0x38/0x8c)
> [ÂÂÂ21.422457]ÂÂr10:00000000 r9:ee914000 r8:ee81d400 r7:00000038
> r6:eeafd400 r5:eeafd464
> [ÂÂÂ21.430296]ÂÂr4:80e08488
> [ÂÂÂ21.432852] [<8018cfc4>] (handle_irq_event_percpu) from
> [<8018d098>] (handle_irq_event+0x48/0x6c)
> [ÂÂÂ21.441736]ÂÂr6:eeafd464 r5:eeafd464 r4:eeafd400
> [ÂÂÂ21.446374] [<8018d050>] (handle_irq_event) from [<8019146c>]
> (handle_fasteoi_irq+0xc4/0x138)
> [ÂÂÂ21.454912]ÂÂr7:00000038 r6:eeafd464 r5:80e10a60 r4:eeafd400
> [ÂÂÂ21.460589] [<801913a8>] (handle_fasteoi_irq) from [<8018bd9c>]
> (generic_handle_irq+0x28/0x38)
> [ÂÂÂ21.469214]ÂÂr7:00000038 r6:80d92ae4 r5:00000000 r4:00000000
> [ÂÂÂ21.474893] [<8018bd74>] (generic_handle_irq) from [<8018c48c>]
> (__handle_domain_irq+0xb0/0xc4)
> [ÂÂÂ21.483611] [<8018c3dc>] (__handle_domain_irq) from [<80102330>]
> (gic_handle_irq+0x68/0xa0)
> [ÂÂÂ21.491978]ÂÂr9:ee914000 r8:f4001100 r7:80e5c6bc r6:ee915f00
> r5:80e08c3c r4:f4000100
> [ÂÂÂ21.499738] [<801022c8>] (gic_handle_irq) from [<801019f0>]
> (__irq_svc+0x70/0xb0)
> [ÂÂÂ21.507233] Exception stack(0xee915f00 to 0xee915f48)
> [ÂÂÂ21.512303] 5f00: 00000001 00000004 00000000 ee926c00 ee9270a8
> ee926c00 ecc45e00 ee9270a8
> [ÂÂÂ21.520498] 5f20: 80ec23b0 ee914000 00000000 ee915f64 ee915f20
> ee915f50 8017c7c0 809b78ac
> [ÂÂÂ21.528687] 5f40: 20070013 ffffffff
> [ÂÂÂ21.532193]ÂÂr9:ee914000 r8:80ec23b0 r7:ee915f34 r6:ffffffff
> r5:20070013 r4:809b78ac
> [ÂÂÂ21.539959] [<809b7874>] (_raw_spin_unlock_irq) from [<8014e98c>]
> (task_work_run+0x90/0xb8)
> [ÂÂÂ21.548321]ÂÂr5:ee926c00 r4:ecc45e00
> [ÂÂÂ21.551913] [<8014e8fc>] (task_work_run) from [<8010da3c>]
> (do_work_pending+0xc8/0xd0)
> [ÂÂÂ21.559848]ÂÂr9:ee914000 r8:801011c4 r7:ee915fb0 r6:ffffe000
> r5:00000004 r4:801011c4
> [ÂÂÂ21.567608] [<8010d974>] (do_work_pending) from [<80101034>]
> (slow_work_pending+0xc/0x20)
> [ÂÂÂ21.575797] Exception stack(0xee915fb0 to 0xee915ff8)
> [ÂÂÂ21.580864] 5fa0:ÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂÂ00000000
> 020c34e8 46059f00 00000000
> [ÂÂÂ21.589059] 5fc0: 00000002 76f133a4 020df680 00000006 76e6e168
> 00000035 7ef81778 00000035
> [ÂÂÂ21.597253] 5fe0: 00000006 7ef816a0 76c75d67 76c77e86 20070030
> 00000039
> [ÂÂÂ21.603883]ÂÂr7:00000006 r6:020df680 r5:76f133a4 r4:00000002
> 
> Am Donnerstag, den 14.06.2018, 22:02 +0800 schrieb Robin Gong:
> > 
> > The legacy sdma driver has below limitations or drawbacks:
> > Â 1. Hardcode the max BDs number as "PAGE_SIZE / sizeof(*)", and
> > alloc
> > ÂÂÂÂÂone page size for one channel regardless of only few BDs
> > needed
> > ÂÂÂÂÂmost time. But in few cases, the max PAGE_SIZE maybe not
> > enough.
> > Â 2. One SDMA channel can't stop immediatley once channel disabled
> > which
> > ÂÂÂÂÂmeans SDMA interrupt may come in after this channel
> > terminated.There
> > ÂÂÂÂÂare some patches for this corner case such as commit
> > "2746e2c389f9",
> > ÂÂÂÂÂbut not cover non-cyclic.
> > 
> > The common virt-dma overcomes the above limitations. It can alloc
> > bd
> > dynamically and free bd once this tx transfer done. No memory
> > wasted or
> > maximum limititation here, only depends on how many memory can be
> > requested
> > from kernel. For No.2, such issue can be workaround by checking if
> > there
> > is available descript("sdmac->desc") now once the unwanted
> > interrupt
> > coming. At last the common virt-dma is easier for sdma driver
> > maintain.
> > 
> > Change from v3:
> > Â 1. add two uart patches which impacted by this patchset.
> > Â 2. unlock 'vc.lock' before cyclic dma callback and lock again
> > after
> > ÂÂÂÂÂit because some driver such as uart will call
> > dmaengine_tx_status
> > ÂÂÂÂÂwhich will acquire 'vc.lock' again and dead lock comes out.
> > Â 3. remove 'Revert commit' stuff since that patch is not wrong and
> > ÂÂÂÂÂcombine two patch into one patch as Sascha's comment.
> > 
> > Change from v2:
> > Â 1. include Sascha's patch to make the main patch easier to
> > review.
> > ÂÂÂÂÂThanks Sacha.
> > Â 2. remove useless 'desc'/'chan' in struct sdma_channe.
> > 
> > Change from v1:
> > Â 1. split v1 patch into 5 patches.
> > Â 2. remove some unnecessary condition check.
> > Â 3. remove unnecessary 'pending' list.
> > 
> > Robin Gong (6):
> > Â tty: serial: imx: correct dma cookie status
> > Â dmaengine: imx-sdma: add virt-dma support
> > Â dmaengine: imx-sdma: remove useless 'lock' and 'enabled' in
> > 'struct
> > ÂÂÂÂsdma_channel'
> > Â dmaengine: imx-sdma: remove the maximum limitation for bd numbers
> > Â dmaengine: imx-sdma: add sdma_transfer_init to decrease code
> > overlap
> > Â tty: serial: imx: split all dma setup operations out of
> > 'port.lock'
> > ÂÂÂÂprotector
> > 
> > Sascha Hauer (1):
> > Â dmaengine: imx-sdma: factor out a struct sdma_desc from struct
> > ÂÂÂÂsdma_channel
> > 
> > Âdrivers/dma/KconfigÂÂÂÂÂÂ|ÂÂÂ1 +
> > Âdrivers/dma/imx-sdma.cÂÂÂ| 394 +++++++++++++++++++++++++++------
> > --------------
> > Âdrivers/tty/serial/imx.c |ÂÂ99 ++++++------
> > Â3 files changed, 282 insertions(+), 212 deletions(-)
> >