Re: [Intel-gfx] [PATCH v3 1/6] drm/i915: Initialize dkl_phy spin lock from display code path

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Apr 10, 2023 at 11:32:14AM -0700, José Roberto de Souza wrote:
> Start to move the initialization of some lock from
> i915_driver_early_probe().
> No dkl function is called prior to intel_setup_outputs(), so this is
> a good place to initialize it.

I disagree. We don't want to sprinke these all over the place.

> This will also fix a warning in Xe kmd:
> 
> [  201.894839] xe 0000:00:02.0: [drm] [ENCODER:235:DDI A/PHY A] failed to retrieve link info, disabling eDP
> [  202.136336] xe 0000:00:02.0: [drm] *ERROR* Failed to write source OUI
> [  202.175346] INFO: trying to register non-static key.
> [  202.175347] irq event stamp: 754060
> [  202.175359] hardirqs last  enabled at (754059): [<ffffffff8122cf79>] tick_nohz_idle_enter+0x59/0x80
> [  202.180294] The code is fine but needs lockdep annotation, or maybe
> [  202.183774] hardirqs last disabled at (754060): [<ffffffff811a5539>] do_idle+0x99/0x230
> [  202.192734] you didn't initialize this object before use?
> [  202.198951] softirqs last  enabled at (753948): [<ffffffff8114abae>] irq_exit_rcu+0xbe/0x130
> [  202.206882] turning off the locking correctness validator.
> [  202.212236] softirqs last disabled at (753943): [<ffffffff8114abae>] irq_exit_rcu+0xbe/0x130
> [  202.220592] CPU: 2 PID: 1415 Comm: modprobe Tainted: G        W          6.3.0-rc4+zeh-xe+ #909
> [  202.243002] Hardware name: Intel Corporation Raptor Lake Client Platform/RaptorLake-P LP5 RVP, BIOS RPLPFWI1.R00.3361.A14.2211151548 11/15/2022
> [  202.255737] Call Trace:
> [  202.258179]  <TASK>
> [  202.260275]  dump_stack_lvl+0x58/0xc0
> [  202.263922]  register_lock_class+0x756/0x7d0
> [  202.268165]  ? find_held_lock+0x2b/0x80
> [  202.271975]  __lock_acquire+0x72/0x28b0
> [  202.275786]  ? debug_object_free+0xb4/0x160
> [  202.279946]  lock_acquire+0xd1/0x2d0
> [  202.283503]  ? intel_dkl_phy_read+0x18/0x60 [xe]
> [  202.288181]  _raw_spin_lock+0x2a/0x40
> [  202.291825]  ? intel_dkl_phy_read+0x18/0x60 [xe]
> [  202.296475]  intel_dkl_phy_read+0x18/0x60 [xe]
> [  202.300949]  icl_aux_power_well_enable+0x2bd/0x400 [xe]
> [  202.306202]  ? intel_display_power_grab_async_put_ref+0x75/0x120 [xe]
> [  202.312649]  intel_power_well_enable+0x1c/0x70 [xe]
> [  202.317543]  __intel_display_power_get_domain.part.0+0x4d/0x70 [xe]
> [  202.323812]  intel_display_power_get+0x43/0x70 [xe]
> [  202.328708]  intel_tc_port_init+0x199/0x2a0 [xe]
> [  202.333363]  intel_ddi_init+0x6ad/0xb00 [xe]
> [  202.337678]  intel_modeset_init_nogem+0x536/0x6d0 [xe]
> [  202.342838]  xe_display_init_noaccel+0x19/0x40 [xe]
> [  202.347743]  xe_device_probe+0x1f5/0x2a0 [xe]
> [  202.352127]  xe_pci_probe+0x28c/0x480 [xe]
> [  202.356260]  pci_device_probe+0x9d/0x150
> [  202.360164]  really_probe+0x19a/0x400
> [  202.363809]  ? __pfx___driver_attach+0x10/0x10
> [  202.368226]  __driver_probe_device+0x73/0x170
> [  202.372558]  driver_probe_device+0x1a/0x90
> [  202.376632]  __driver_attach+0xcd/0x1c0
> [  202.380442]  bus_for_each_dev+0x72/0xc0
> [  202.384253]  bus_add_driver+0x110/0x210
> [  202.388063]  driver_register+0x50/0x100
> [  202.391873]  ? __pfx_init_module+0x10/0x10 [xe]
> [  202.396431]  do_one_initcall+0x55/0x260
> [  202.400245]  ? rcu_is_watching+0xd/0x40
> [  202.404058]  ? kmalloc_trace+0xa0/0xb0
> [  202.407786]  do_init_module+0x45/0x1e0
> [  202.411512]  __do_sys_finit_module+0xac/0x120
> [  202.415838]  do_syscall_64+0x37/0x90
> [  202.419397]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
> [  202.424409] RIP: 0033:0x7fd11291ea3d
> [  202.427967] Code: 5b 41 5c c3 66 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d c3 a3 0f 00 f7 d8 64 89 01 48
> [  202.446530] RSP: 002b:00007ffffde11368 EFLAGS: 00000246 ORIG_RAX: 0000000000000139
> [  202.454031] RAX: ffffffffffffffda RBX: 00005616a617f210 RCX: 00007fd11291ea3d
> [  202.461106] RDX: 0000000000000000 RSI: 00005616a617fe60 RDI: 000000000000000e
> [  202.468182] RBP: 0000000000040000 R08: 0000000000000000 R09: 0000000000000002
> [  202.475250] R10: 000000000000000e R11: 0000000000000246 R12: 00005616a617fe60
> [  202.482319] R13: 00005616a617f340 R14: 0000000000000000 R15: 00005616a6180650
> [  202.489396]  </TASK>
> 
> Cc: intel-gfx@lists.freedesktop.org
> Cc: intel-xe@lists.freedesktop.org
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/i915/display/intel_display.c | 3 +++
>  drivers/gpu/drm/i915/display/intel_dkl_phy.c | 6 ++++++
>  drivers/gpu/drm/i915/display/intel_dkl_phy.h | 2 ++
>  drivers/gpu/drm/i915/i915_driver.c           | 1 -
>  4 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
> index 24c96f388d521..cf3a3b3afdd13 100644
> --- a/drivers/gpu/drm/i915/display/intel_display.c
> +++ b/drivers/gpu/drm/i915/display/intel_display.c
> @@ -83,6 +83,7 @@
>  #include "intel_display_debugfs.h"
>  #include "intel_display_power.h"
>  #include "intel_display_types.h"
> +#include "intel_dkl_phy.h"
>  #include "intel_dmc.h"
>  #include "intel_dp.h"
>  #include "intel_dp_link_training.h"
> @@ -7883,6 +7884,8 @@ static void intel_setup_outputs(struct drm_i915_private *dev_priv)
>  	if (!HAS_DISPLAY(dev_priv))
>  		return;
>  
> +	intel_dkl_phy_init(dev_priv);
> +
>  	if (IS_DG2(dev_priv)) {
>  		intel_ddi_init(dev_priv, PORT_A);
>  		intel_ddi_init(dev_priv, PORT_B);
> diff --git a/drivers/gpu/drm/i915/display/intel_dkl_phy.c b/drivers/gpu/drm/i915/display/intel_dkl_phy.c
> index 57cc3edba0163..5bce7b5b27bc7 100644
> --- a/drivers/gpu/drm/i915/display/intel_dkl_phy.c
> +++ b/drivers/gpu/drm/i915/display/intel_dkl_phy.c
> @@ -104,3 +104,9 @@ intel_dkl_phy_posting_read(struct drm_i915_private *i915, struct intel_dkl_phy_r
>  
>  	spin_unlock(&i915->display.dkl.phy_lock);
>  }
> +
> +void
> +intel_dkl_phy_init(struct drm_i915_private *i915)
> +{
> +	spin_lock_init(&i915->display.dkl.phy_lock);
> +}
> diff --git a/drivers/gpu/drm/i915/display/intel_dkl_phy.h b/drivers/gpu/drm/i915/display/intel_dkl_phy.h
> index 570ee36f9386f..615429b6392c5 100644
> --- a/drivers/gpu/drm/i915/display/intel_dkl_phy.h
> +++ b/drivers/gpu/drm/i915/display/intel_dkl_phy.h
> @@ -20,5 +20,7 @@ void
>  intel_dkl_phy_rmw(struct drm_i915_private *i915, struct intel_dkl_phy_reg reg, u32 clear, u32 set);
>  void
>  intel_dkl_phy_posting_read(struct drm_i915_private *i915, struct intel_dkl_phy_reg reg);
> +void
> +intel_dkl_phy_init(struct drm_i915_private *i915);
>  
>  #endif /* __INTEL_DKL_PHY_H__ */
> diff --git a/drivers/gpu/drm/i915/i915_driver.c b/drivers/gpu/drm/i915/i915_driver.c
> index 066d79c2069c4..6fe1a97cc246d 100644
> --- a/drivers/gpu/drm/i915/i915_driver.c
> +++ b/drivers/gpu/drm/i915/i915_driver.c
> @@ -224,7 +224,6 @@ static int i915_driver_early_probe(struct drm_i915_private *dev_priv)
>  	mutex_init(&dev_priv->display.wm.wm_mutex);
>  	mutex_init(&dev_priv->display.pps.mutex);
>  	mutex_init(&dev_priv->display.hdcp.comp_mutex);
> -	spin_lock_init(&dev_priv->display.dkl.phy_lock);
>  
>  	i915_memcpy_init_early(dev_priv);
>  	intel_runtime_pm_init_early(&dev_priv->runtime_pm);
> -- 
> 2.40.0

-- 
Ville Syrjälä
Intel