Messages in this thread Patch in this message | | | Date | Tue, 25 Jun 2019 11:14:45 +0530 | From | dhar@codeauro ... | Subject | Re: drm/msm/dpu: Correct dpu encoder spinlock initialization |
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On 2019-06-25 03:56, Jeykumar Sankaran wrote: > On 2019-06-23 23:27, Shubhashree Dhar wrote: >> dpu encoder spinlock should be initialized during dpu encoder >> init instead of dpu encoder setup which is part of commit. >> There are chances that vblank control uses the uninitialized >> spinlock if not initialized during encoder init. > Not much can be done if someone is performing a vblank operation > before encoder_setup is done. > Can you point to the path where this lock is acquired before > the encoder_setup? > > Thanks > Jeykumar S. >>
When running some dp usecase, we are hitting this callstack.
Process kworker/u16:8 (pid: 215, stack limit = 0x00000000df9dd930) Call trace: spin_dump+0x84/0x8c spin_dump+0x0/0x8c do_raw_spin_lock+0x80/0xb0 _raw_spin_lock_irqsave+0x34/0x44 dpu_encoder_toggle_vblank_for_crtc+0x8c/0xe8 dpu_crtc_vblank+0x168/0x1a0 dpu_kms_enable_vblank+0[ 11.648998] vblank_ctrl_worker+0x3c/0x60 process_one_work+0x16c/0x2d8 worker_thread+0x1d8/0x2b0 kthread+0x124/0x134
Looks like vblank is getting enabled earlier causing this issue and we are using the spinlock without initializing it.
Thanks, Shubhashree
>> Change-Id: I5a18b95fa47397c834a266b22abf33a517b03a4e >> Signed-off-by: Shubhashree Dhar <dhar@codeaurora.org> >> --- >> drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c | 3 +-- >> 1 file changed, 1 insertion(+), 2 deletions(-) >> >> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c >> b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c >> index 5f085b5..22938c7 100644 >> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c >> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c >> @@ -2195,8 +2195,6 @@ int dpu_encoder_setup(struct drm_device *dev, >> struct >> drm_encoder *enc, >> if (ret) >> goto fail; >> >> - spin_lock_init(&dpu_enc->enc_spinlock); >> - >> atomic_set(&dpu_enc->frame_done_timeout, 0); >> timer_setup(&dpu_enc->frame_done_timer, >> dpu_encoder_frame_done_timeout, 0); >> @@ -2250,6 +2248,7 @@ struct drm_encoder *dpu_encoder_init(struct >> drm_device *dev, >> >> drm_encoder_helper_add(&dpu_enc->base, &dpu_encoder_helper_funcs); >> >> + spin_lock_init(&dpu_enc->enc_spinlock); >> dpu_enc->enabled = false; >> >> return &dpu_enc->base;
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