From bc5f2ab11ca6dda4a4826e7e78d5365d7c3e1569 Mon Sep 17 00:00:00 2001 From: Rodrigo Vivi Date: Wed, 23 Sep 2015 11:32:36 -0700 Subject: [PATCH] drm/i915/skl: Don't call intel_prepare_ddi when encoder list isn't yet initialized. In case something goes wrong with power well initialization we were calling intel_prepare_ddi during boot while encoder list isnt't initilized. [ 9.618747] i915 0000:00:02.0: Invalid ROM contents [ 9.631446] [drm] failed to find VBIOS tables [ 9.720036] BUG: unable to handle kernel NULL pointer dereference at 00000000 00000058 [ 9.721986] IP: [] ddi_get_encoder_port+0x82/0x190 [i915] [ 9.723736] PGD 0 [ 9.724286] Oops: 0000 [#1] PREEMPT SMP [ 9.725386] Modules linked in: intel_powerclamp snd_hda_intel(+) coretemp crc 32c_intel snd_hda_codec snd_hda_core serio_raw snd_pcm snd_timer i915(+) parport _pc parport pinctrl_sunrisepoint pinctrl_intel nfsd nfs_acl [ 9.730635] CPU: 0 PID: 497 Comm: systemd-udevd Not tainted 4.3.0-rc2-eywa-10 967-g72de2cfd-dirty #2 [ 9.732785] Hardware name: Intel Corporation Cannonlake Client platform/Skyla ke DT DDR4 RVP8, BIOS CNLSE2R1.R00.X021.B00.1508040310 08/04/2015 [ 9.735785] task: ffff88008a704700 ti: ffff88016a1ac000 task.ti: ffff88016a1a c000 [ 9.737584] RIP: 0010:[] [] ddi_get_enco der_port+0x82/0x190 [i915] [ 9.739934] RSP: 0000:ffff88016a1af710 EFLAGS: 00010296 [ 9.741184] RAX: 000000000000004e RBX: ffff88008a9edc98 RCX: 0000000000000001 [ 9.742934] RDX: 000000000000004e RSI: ffffffff81fc1e82 RDI: 00000000ffffffff [ 9.744634] RBP: ffff88016a1af730 R08: 0000000000000000 R09: 0000000000000578 [ 9.746333] R10: 0000000000001065 R11: 0000000000000578 R12: fffffffffffffff8 [ 9.748033] R13: ffff88016a1af7a8 R14: ffff88016a1af794 R15: 0000000000000000 [ 9.749733] FS: 00007eff2e1e07c0(0000) GS:ffff88016fc00000(0000) knlGS:00000 00000000000 [ 9.751683] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 9.753083] CR2: 0000000000000058 CR3: 000000016922b000 CR4: 00000000003406f0 [ 9.754782] Stack: [ 9.755332] ffff88008a9edc98 ffff88008a9ed800 ffffffffa01d07b0 00000000fffb9 09e [ 9.757232] ffff88016a1af7d8 ffffffffa0154ea7 0000000000000246 ffff88016a370 080 [ 9.759182] ffff88016a370080 ffff88008a9ed800 0000000000000246 ffff88008a9ed c98 [ 9.761132] Call Trace: [ 9.761782] [] intel_prepare_ddi+0x67/0x860 [i915] [ 9.763332] [] ? _raw_spin_unlock_irqrestore+0x26/0x40 [ 9.765031] [] ? gen9_read32+0x141/0x360 [i915] [ 9.766531] [] skl_set_power_well+0x431/0xa80 [i915] [ 9.768181] [] skl_power_well_enable+0x13/0x20 [i915] [ 9.769781] [] intel_power_well_enable+0x28/0x50 [i915] [ 9.771481] [] intel_display_power_get+0x92/0xc0 [i915] [ 9.773180] [] intel_display_set_init_power+0x3b/0x40 [i91 5] [ 9.774980] [] intel_power_domains_init_hw+0x120/0x520 [i9 15] [ 9.776780] [] i915_driver_load+0xb21/0xf40 [i915] So let's protect this case. My first attempt was to remove the intel_prepare_ddi, but Daniel had pointed out this is really needed to restore those registers values. And Imre pointed out that this case was without the flag protection and this was actually where things were going bad. So I've just checked and this indeed solves my issue. The regressing intel_prepare_ddi call was added in commit 1d2b9526a790d55b7ae870934a74937081f62de2 Author: Damien Lespiau Date: Fri Mar 6 18:50:53 2015 +0000 drm/i915/skl: Restore the DDI translation tables when enabling PW1 Cc: Imre Deak Cc: Daniel Vetter Signed-off-by: Rodrigo Vivi Reviewed-by: Imre Deak [Jani: regression reference] Signed-off-by: Jani Nikula --- drivers/gpu/drm/i915/intel_runtime_pm.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index af7fdb3bd663ae..7401cf90b0dbcd 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -246,7 +246,8 @@ static void skl_power_well_post_enable(struct drm_i915_private *dev_priv, } if (power_well->data == SKL_DISP_PW_1) { - intel_prepare_ddi(dev); + if (!dev_priv->power_domains.initializing) + intel_prepare_ddi(dev); gen8_irq_power_well_post_enable(dev_priv, 1 << PIPE_A); } }