[Intel-xe] [Intel-gfx] [PATCH v4] drm/i915: Initialize dkl_phy spin lock from display code path

Thu Apr 20 13:19:09 UTC 2023

On Wed, 2023-04-19 at 00:29 -0700, Lucas De Marchi wrote:
> On Wed, Apr 19, 2023 at 10:16:22AM +0300, Jani Nikula wrote:
> > On Tue, 18 Apr 2023, Lucas De Marchi <lucas.demarchi at intel.com> wrote:
> > > On Tue, Apr 18, 2023 at 11:30:18PM -0700, Lucas De Marchi wrote:
> > > > On Tue, Apr 18, 2023 at 09:43:37AM -0700, Jose Souza wrote:
> > > > > Start to move the initialization of display locks from
> > > > > i915_driver_early_probe(), this way it is also executed when running
> > > > > Xe kmd.
> > > > > 
> > > > > This will 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>
> > > > > 
> > > > > v2:
> > > > > - added intel_display_locks_init()
> > > > > 
> > > > > v3:
> > > > > - rebased
> > > > > 
> > > > > v4:
> > > > > - drop intel_display_locks_init()
> > > > 
> > > > why?
> > > 
> > > ah... ok, now we have intel_display_driver_early_probe(). I thought you
> > > were dropping the call from i915_driver.c
> > > 
> > > Remaining question for display: do we want to spread the lock
> > > initialization to each compilation unit?  Or should we just keep a
> > > 
> > > 	static locks_init() { <all the locks here> }
> > > 
> > > the lock init seems a very cheap init that maybe doesn't deserve to be
> > > spread. Then this patch could just move all the mutexes initialization
> > > that were left behind.
> > 
> > I still think if only one file uses something, then that file should
> > include the init for it too, and nobody else should touch it. Including
> > locks. Ideally, they would be stowed away in allocated opaque structs
> > that can't even be accessed (or initialized) by anyone else.
> 
> so... this version of the patch?  We will need to spread the mutexes
> around then.

Do we have an agreement here?
I'm also in favor of init all variables in the only file that touches it.

The other mutexes can be moved gradually.

> 
> Lucas De Marchi
> 
> > 
> > BR,
> > Jani.
> > 
> > 
> > -- 
> > Jani Nikula, Intel Open Source Graphics Center