Re: [Intel-gfx] [PATCH v2 1/4] drm/i915: Fix system suspend without fbdev being initialized

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 08 Feb 2023, Imre Deak <imre.deak@intel.com> wrote:
> If fbdev is not initialized for some reason - in practice on platforms
> without display - suspending fbdev should be skipped during system
> suspend, fix this up. While at it add an assert that suspending fbdev
> only happens with the display present.
>
> This fixes the following:
>
> [   91.227923] PM: suspend entry (s2idle)
> [   91.254598] Filesystems sync: 0.025 seconds
> [   91.270518] Freezing user space processes
> [   91.272266] Freezing user space processes completed (elapsed 0.001 seconds)
> [   91.272686] OOM killer disabled.
> [   91.272872] Freezing remaining freezable tasks
> [   91.274295] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
> [   91.659622] BUG: kernel NULL pointer dereference, address: 00000000000001c8
> [   91.659981] #PF: supervisor write access in kernel mode
> [   91.660252] #PF: error_code(0x0002) - not-present page
> [   91.660511] PGD 0 P4D 0
> [   91.660647] Oops: 0002 [#1] PREEMPT SMP NOPTI
> [   91.660875] CPU: 4 PID: 917 Comm: bash Not tainted 6.2.0-rc7+ #54
> [   91.661185] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS edk2-20221117gitfff6d81270b5-9.fc37 unknown
> [   91.661680] RIP: 0010:mutex_lock+0x19/0x30
> [   91.661914] Code: 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 53 48 89 fb e8 62 d3 ff ff 31 c0 65 48 8b 14 25 00 15 03 00 <f0> 48 0f b1 13 75 06 5b c3 cc cc cc cc 48 89 df 5b eb b4 0f 1f 40
> [   91.662840] RSP: 0018:ffffa1e8011ffc08 EFLAGS: 00010246
> [   91.663087] RAX: 0000000000000000 RBX: 00000000000001c8 RCX: 0000000000000000
> [   91.663440] RDX: ffff8be455eb0000 RSI: 0000000000000001 RDI: 00000000000001c8
> [   91.663802] RBP: ffff8be459440000 R08: ffff8be459441f08 R09: ffffffff8e1432c0
> [   91.664167] R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000001
> [   91.664532] R13: 00000000000001c8 R14: 0000000000000000 R15: ffff8be442f4fb20
> [   91.664905] FS:  00007f28ffc16740(0000) GS:ffff8be4bb900000(0000) knlGS:0000000000000000
> [   91.665334] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> [   91.665626] CR2: 00000000000001c8 CR3: 0000000114926006 CR4: 0000000000770ee0
> [   91.665988] PKRU: 55555554
> [   91.666131] Call Trace:
> [   91.666265]  <TASK>
> [   91.666381]  intel_fbdev_set_suspend+0x97/0x1b0 [i915]
> [   91.666738]  i915_drm_suspend+0xb9/0x100 [i915]
> [   91.667029]  pci_pm_suspend+0x78/0x170
> [   91.667234]  ? __pfx_pci_pm_suspend+0x10/0x10
> [   91.667461]  dpm_run_callback+0x47/0x150
> [   91.667673]  __device_suspend+0x10a/0x4e0
> [   91.667880]  dpm_suspend+0x134/0x270
> [   91.668069]  dpm_suspend_start+0x79/0x80
> [   91.668272]  suspend_devices_and_enter+0x11b/0x890
> [   91.668526]  pm_suspend.cold+0x270/0x2fc
> [   91.668737]  state_store+0x46/0x90
> [   91.668916]  kernfs_fop_write_iter+0x11b/0x200
> [   91.669153]  vfs_write+0x1e1/0x3a0
> [   91.669336]  ksys_write+0x53/0xd0
> [   91.669510]  do_syscall_64+0x58/0xc0
> [   91.669699]  ? syscall_exit_to_user_mode_prepare+0x18e/0x1c0
> [   91.669980]  ? syscall_exit_to_user_mode_prepare+0x18e/0x1c0
> [   91.670278]  ? syscall_exit_to_user_mode+0x17/0x40
> [   91.670524]  ? do_syscall_64+0x67/0xc0
> [   91.670717]  ? __irq_exit_rcu+0x3d/0x140
> [   91.670931]  entry_SYSCALL_64_after_hwframe+0x72/0xdc
> [   91.671202] RIP: 0033:0x7f28ffd14284
>
> Fixes: f8cc091e0530 ("drm/i915/fbdev: suspend HPD before fbdev unregistration")
> References: https://gitlab.freedesktop.org/drm/intel/-/issues/8015
> Tested-by: iczero <iczero@hellomouse.net>
> Cc: Andrzej Hajda <andrzej.hajda@intel.com>
> Cc: iczero <iczero@hellomouse.net>
> Signed-off-by: Imre Deak <imre.deak@intel.com>

Cc: <stable@vger.kernel.org> # v6.1+
Reviewed-by: Jani Nikula <jani.nikula@intel.com>

> ---
>  drivers/gpu/drm/i915/display/intel_fbdev.c | 8 +++++++-
>  1 file changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev.c b/drivers/gpu/drm/i915/display/intel_fbdev.c
> index 81b41148e592b..e719202d831f0 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev.c
> @@ -632,7 +632,13 @@ void intel_fbdev_set_suspend(struct drm_device *dev, int state, bool synchronous
>  	struct intel_fbdev *ifbdev = dev_priv->display.fbdev.fbdev;
>  	struct fb_info *info;
>  
> -	if (!ifbdev || !ifbdev->vma)
> +	if (!ifbdev)
> +		return;
> +
> +	if (drm_WARN_ON(&dev_priv->drm, !HAS_DISPLAY(dev_priv)))
> +		return;
> +
> +	if (!ifbdev->vma)
>  		goto set_suspend;
>  
>  	info = ifbdev->helper.info;

-- 
Jani Nikula, Intel Open Source Graphics Center