[Intel-gfx] [PATCH] drm/i915: check the power wells on assert_{cursor, plane}

[Paulo Zanoni]

2014-07-17 5:38 GMT-03:00 Daniel Vetter <daniel at ffwll.ch>:
> On Wed, Jul 16, 2014 at 05:06:34PM -0300, Paulo Zanoni wrote:
>> From: Paulo Zanoni <paulo.r.zanoni at intel.com>
>>
>> Since we merged runtime PM support for DPMS, it is possible that these
>> functions will be called when the power wells are disabled but a mode
>> is "set", resulting in "failed assertion" and "device suspended while
>> reading register" WARNs.
>>
>> To reproduce the bug: disable all screens using mode unset, do a
>> modeset on one screen, disable it using DPMS, then try to do a mode
>> unset on it again to see the WARNs.
>>
>> Testcase: igt/rpm_rpm/dpms-mode-unset-lpsp
>> Testcase: igt/rpm_rpm/dpms-mode-unset-non-lpsp
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>
> Hm, where do we call these asserts while the pipe is off? Do you have some
> example backtraces at hand?

Function __intel_set_mode() directly calls intel_crtc_disable(), which
calls both assert_plane_disabled() and assert_cursor_disabled().


> -Daniel
>
>> ---
>>  drivers/gpu/drm/i915/intel_display.c | 14 ++++++++++----
>>  1 file changed, 10 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
>> index 54e3af9..7ad46e2 100644
>> --- a/drivers/gpu/drm/i915/intel_display.c
>> +++ b/drivers/gpu/drm/i915/intel_display.c
>> @@ -1216,7 +1216,9 @@ static void assert_cursor(struct drm_i915_private *dev_priv,
>>       struct drm_device *dev = dev_priv->dev;
>>       bool cur_state;
>>
>> -     if (IS_845G(dev) || IS_I865G(dev))
>> +     if (!intel_display_power_enabled(dev_priv, POWER_DOMAIN_PIPE(pipe)))
>> +             cur_state = false;
>> +     else if (IS_845G(dev) || IS_I865G(dev))
>>               cur_state = I915_READ(_CURACNTR) & CURSOR_ENABLE;
>>       else
>>               cur_state = I915_READ(CURCNTR(pipe)) & CURSOR_MODE;
>> @@ -1262,9 +1264,13 @@ static void assert_plane(struct drm_i915_private *dev_priv,
>>       u32 val;
>>       bool cur_state;
>>
>> -     reg = DSPCNTR(plane);
>> -     val = I915_READ(reg);
>> -     cur_state = !!(val & DISPLAY_PLANE_ENABLE);
>> +     if (!intel_display_power_enabled(dev_priv, POWER_DOMAIN_PIPE(plane))) {
>> +             cur_state = false;
>> +     } else {
>> +             reg = DSPCNTR(plane);
>> +             val = I915_READ(reg);
>> +             cur_state = !!(val & DISPLAY_PLANE_ENABLE);
>> +     }
>>       WARN(cur_state != state,
>>            "plane %c assertion failure (expected %s, current %s)\n",
>>            plane_name(plane), state_string(state), state_string(cur_state));
>> --
>> 2.0.0
>>
>> _______________________________________________
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>> Intel-gfx at lists.freedesktop.org
>> 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