[Intel-gfx] [PATCH 3/7] drm/i915: don't read pp_ctrl_reg if we're suspended

[Paulo Zanoni]

2014-04-01 17:37 GMT-03:00 Daniel Vetter <daniel at ffwll.ch>:
> On Tue, Apr 01, 2014 at 02:55:09PM -0300, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>
>> ... at edp_have_panel_vdd. Just return false, saying we don't have the
>> panel VDD since the device is suspended.
>>
>> We started getting WARNs about this problem since the patch that
>> started checking if we're suspended while reading registers.
>>
>> Testcase: igt/pm_pc8
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> Hm, where's an example backtrace for this? I wonder whether we simply need
> to extend the range where we hold the runtime pm ref a bit ...

There are tons of WARNs, but here is one example:

[   63.572201] [drm:hsw_enable_pc8] Enabling package C8+
[   63.581831] [drm:i915_runtime_suspend] Device suspended
[   63.664798] ------------[ cut here ]------------
[   63.664824] WARNING: CPU: 3 PID: 828 at
drivers/gpu/drm/i915/intel_uncore.c:47
assert_device_not_suspended.isra.7+0x32/0x40 [i915]()
[   63.664826] Device suspended
[   63.664828] Modules linked in: ccm fuse ip6table_filter ip6_tables
ebtable_nat ebtables arc4 ath9k_htc ath9k_common ath9k_hw mac80211 ath
cfg80211 iTCO_wdt iTCO_vendor_support x86_pkg_temp_thermal coretemp
microcode i2c_i801 e1000e pcspkr serio_raw lpc_ich ptp pps_core mei_me
mei mfd_core dm_crypt i915 crc32_pclmul crc32c_intel
ghash_clmulni_intel i2c_algo_bit drm_kms_helper drm video
[   63.664867] CPU: 3 PID: 828 Comm: kworker/3:3 Not tainted 3.14.0+ #153
[   63.664869] Hardware name: Intel Corporation Shark Bay Client
platform/WhiteTip Mountain 1, BIOS HSWLPTU1.86C.0133.R00.1309172123
09/17/2013
[   63.664887] Workqueue: events edp_panel_vdd_work [i915]
[   63.664889]  0000000000000009 ffff88009d745c28 ffffffff8167ec6f
ffff88009d745c70
[   63.664895]  ffff88009d745c60 ffffffff8106c8ed ffff880036278000
00000000000c7204
[   63.664900]  ffff88014f2d3040 ffff880036278070 0000000000000001
ffff88009d745cc0
[   63.664905] Call Trace:
[   63.664911]  [<ffffffff8167ec6f>] dump_stack+0x4d/0x66
[   63.664916]  [<ffffffff8106c8ed>] warn_slowpath_common+0x7d/0xa0
[   63.664920]  [<ffffffff8106c95c>] warn_slowpath_fmt+0x4c/0x50
[   63.664926]  [<ffffffff810bd6be>] ? mark_held_locks+0xae/0x130
[   63.664941]  [<ffffffffa00d80d2>]
assert_device_not_suspended.isra.7+0x32/0x40 [i915]
[   63.664956]  [<ffffffffa00d99d2>] gen6_read32+0x32/0x120 [i915]
[   63.664969]  [<ffffffffa00d99a0>] ? gen6_read8+0x120/0x120 [i915]
[   63.664985]  [<ffffffffa0106f8f>] edp_have_panel_vdd+0x3f/0x50 [i915]
[   63.665000]  [<ffffffffa01074e8>] edp_panel_vdd_off_sync+0x58/0x1c0 [i915]
[   63.665004]  [<ffffffff8108a06c>] ? process_one_work+0x18c/0x560
[   63.665018]  [<ffffffffa0107684>] edp_panel_vdd_work+0x34/0x50 [i915]
[   63.665022]  [<ffffffff8108a0d7>] process_one_work+0x1f7/0x560
[   63.665026]  [<ffffffff8108a06c>] ? process_one_work+0x18c/0x560
[   63.665031]  [<ffffffff8108ae2b>] worker_thread+0x11b/0x3a0
[   63.665035]  [<ffffffff8108ad10>] ? manage_workers.isra.21+0x2a0/0x2a0
[   63.665039]  [<ffffffff810916fc>] kthread+0xfc/0x120
[   63.665043]  [<ffffffff81091600>] ? kthread_create_on_node+0x230/0x230
[   63.665048]  [<ffffffff8169082c>] ret_from_fork+0x7c/0xb0
[   63.665052]  [<ffffffff81091600>] ? kthread_create_on_node+0x230/0x230
[   63.665054] ---[ end trace 1250bcc890af9999 ]---
[   63.665060] [drm:edp_panel_vdd_off_sync] Turning eDP VDD off
[   63.665061] ------------[ cut here ]------------

>
> Whatever, merged (I can rebase afterwards if you supply the backtrace for
> the commit message, there we should at least have it).
> -Daniel
>> ---
>>  drivers/gpu/drm/i915/intel_dp.c | 3 ++-
>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
>> index 6f767e5..44471cc 100644
>> --- a/drivers/gpu/drm/i915/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/intel_dp.c
>> @@ -314,7 +314,8 @@ static bool edp_have_panel_vdd(struct intel_dp *intel_dp)
>>       struct drm_device *dev = intel_dp_to_dev(intel_dp);
>>       struct drm_i915_private *dev_priv = dev->dev_private;
>>
>> -     return (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
>> +     return !dev_priv->pm.suspended &&
>> +            (I915_READ(_pp_ctrl_reg(intel_dp)) & EDP_FORCE_VDD) != 0;
>>  }
>>
>>  static void
>> --
>> 1.8.5.3
>>
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>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Daniel Vetter
> Software Engineer, Intel Corporation
> +41 (0) 79 365 57 48 - http://blog.ffwll.ch



-- 
Paulo Zanoni