[Intel-gfx] [PATCH v2] drm/i915: Fix assert_plane() warning on bootup with external display

Tue Jun 26 13:01:26 UTC 2018

On Mon, Jun 25, 2018 at 05:33:05PM -0700, Azhar Shaikh wrote:
> On KBL, WHL RVPs, booting up with an external display connected, triggers
> below warning, when the BiOS brings up the external display too.
> This warning is not seen during hotplug.
> 
> [    3.615226] ------------[ cut here ]------------
> [    3.619829] plane 1A assertion failure (expected on, current off)
> [    3.632039] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
> [    3.633920] iwlwifi 0000:00:14.3: loaded firmware version 38.c0e03d94.0 op_mode iwlmvm
> [    3.647157] Modules linked in: iwlwifi cfg80211 btusb btrtl btbcm btintel bluetooth ecdh_generic
> [    3.647163] CPU: 2 PID: 354 Comm: frecon Not tainted 4.17.0-rc7-50176-g655af12d39c2 #3
> [    3.647165] Hardware name: Intel Corporation CoffeeLake Client Platform/WhiskeyLake U DDR4 ERB, BIOS CNLSFWR1.R00.X140.B00.1804040304 04/04/2018
> [    3.684509] RIP: 0010:assert_plane+0x71/0xbb
> [    3.764451] Call Trace:
> [    3.766888]  intel_atomic_commit_tail+0xa97/0xb77
> [    3.771569]  intel_atomic_commit+0x26a/0x279
> [    3.771572]  drm_atomic_helper_set_config+0x5c/0x76
> [    3.780670]  __drm_mode_set_config_internal+0x66/0x109
> [    3.780672]  drm_mode_setcrtc+0x4c9/0x5cc
> [    3.780674]  ? drm_mode_getcrtc+0x162/0x162
> [    3.789774]  ? drm_mode_getcrtc+0x162/0x162
> [    3.798108]  drm_ioctl_kernel+0x8d/0xe4
> [    3.801926]  drm_ioctl+0x27d/0x368
> [    3.805311]  ? drm_mode_getcrtc+0x162/0x162
> [    3.805314]  ? selinux_file_ioctl+0x14e/0x199
> [    3.805317]  vfs_ioctl+0x21/0x2f
> [    3.813812]  do_vfs_ioctl+0x491/0x4b4
> [    3.813813]  ? security_file_ioctl+0x37/0x4b
> [    3.813816]  ksys_ioctl+0x55/0x75
> [    3.820672]  __x64_sys_ioctl+0x1a/0x1e
> [    3.820674]  do_syscall_64+0x51/0x5f
> [    3.820678]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
> [    3.828221] RIP: 0033:0x7b5e04953967
> [    3.835504] RSP: 002b:00007fff2eafb6f8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> [    3.835505] RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007b5e04953967
> [    3.835505] RDX: 00007fff2eafb730 RSI: 00000000c06864a2 RDI: 000000000000000f
> [    3.835506] RBP: 00007fff2eafb720 R08: 0000000000000000 R09: 0000000000000000
> [    3.835507] R10: 0000000000000070 R11: 0000000000000246 R12: 000000000000000f
> [    3.879988] R13: 000056bc9dd7d210 R14: 00007fff2eafb730 R15: 00000000c06864a2
> [    3.887081] Code: 48 c7 c7 06 71 a5 be 84 c0 48 c7 c2 06 fd a3 be 48 89 f9 48 0f 44 ca 84 db 48 0f 45 d7 48 c7 c7 df d3 a4 be 31 c0 e8 af a0 c0 ff <0f> 0b eb 2b 48 c7 c7 06 fd a3 be 84 c0 48 c7 c2 06 71 a5 be 48
> [    3.905845] WARNING: CPU: 2 PID: 354 at drivers/gpu/drm/i915/intel_display.c:1294 assert_plane+0x71/0xbb
> [    3.920964] ---[ end trace dac692f4ac46391a ]---
> 
> The warning is seen when mode_setcrtc() is called for pipeB
> during bootup and before we get a mode_setcrtc() for pipeA,
> while doing update_crtcs() in intel_atomic_commit_tail().
> Now since, plane1A is still active after commit, update_crtcs()
> is done for pipeA and eventually update_plane() for plane1A.
> 
> intel_plane_state->ctl for plane1A is not updated since set_modecrtc() is
> called for pipeB. So intel_plane_state->ctl for plane 1A will be 0x0.
> So doing an update_plane() for plane1A, will result in clearing
> PLANE_CTL_ENABLE bit, and hence the warning.
> 
> To fix this warning, force all active planes to recompute their states
> in probe.
> 
> Signed-off-by: Azhar Shaikh <azhar.shaikh at intel.com>
> ---
> Changes in v2:
> - Force all planes to recompute their states.(Ville Syrjälä)
> - Update the commit message
> 
>  drivers/gpu/drm/i915/intel_display.c | 49 ++++++++++++++++++++++++++++++++++++
>  1 file changed, 49 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 3709fa1b6318..1511d58991cc 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15092,6 +15092,51 @@ static void intel_update_fdi_pll_freq(struct drm_i915_private *dev_priv)
>  	DRM_DEBUG_DRIVER("FDI PLL freq=%d\n", dev_priv->fdi_pll_freq);
>  }
>  
> +static void intel_initial_commit(struct drm_device *dev,
> +				 struct intel_crtc *intel_crtc)
> +{
> +	struct drm_atomic_state *state = NULL;
> +	struct drm_crtc *crtc = &intel_crtc->base;
> +	struct drm_modeset_acquire_ctx ctx;
> +	struct drm_crtc_state *crtc_state;
> +	int ret;
> +
> +	drm_modeset_acquire_init(&ctx, 0);
> +
> +	state = drm_atomic_state_alloc(dev);
> +	if (!state)
> +		goto unlock;
> +
> +	state->acquire_ctx = &ctx;
> +

I would put the for_each_crtc() loop here so that a single atomic commit
will take care of all the active pipes.

> +	crtc_state = drm_atomic_get_crtc_state(state, crtc);
> +	if (IS_ERR(crtc_state))
> +		goto out;
> +
> +	if (!crtc_state->active)
> +		goto out;
> +
> +	ret = drm_atomic_add_affected_planes(state, crtc);
> +	if (ret)
> +		goto out;
> +
> +	ret = drm_atomic_commit(state);
> +	if (ret == -EDEADLK) {
> +		drm_atomic_state_clear(state);
> +		drm_modeset_backoff(&ctx);
> +	}

You're missing the EDEADLK retry loop entirely.

> +
> +out:
> +	if (state) {
> +		drm_atomic_state_put(state);
> +		state = NULL;
> +	}
> +
> +unlock:
> +	drm_modeset_drop_locks(&ctx);
> +	drm_modeset_acquire_fini(&ctx);

We probably want to print an error of some sort if this fails.

> +}
> +
>  int intel_modeset_init(struct drm_device *dev)
>  {
>  	struct drm_i915_private *dev_priv = to_i915(dev);
> @@ -15221,6 +15266,10 @@ int intel_modeset_init(struct drm_device *dev)
>  		intel_find_initial_plane_obj(crtc, &plane_config);
>  	}
>  
> +	/* Force all active planes to recompute their states */
> +	for_each_intel_crtc(dev, crtc)
> +		intel_initial_commit(dev, crtc);
> +
>  	/*
>  	 * Make sure hardware watermarks really match the state we read out.
>  	 * Note that we need to do this after reconstructing the BIOS fb's
> -- 
> 1.9.1

-- 
Ville Syrjälä
Intel