Re: [PATCH] drm/i915/skl: Bypass debug message if scalers are not requested

[Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>]

On 08/05/2015 03:12 PM, Tvrtko Ursulin wrote:
>
> On 08/05/2015 02:58 PM, Daniel Vetter wrote:
>> On Wed, Aug 05, 2015 at 02:20:17PM +0100, Tvrtko Ursulin wrote:
>>>
>>> On 05/04/2015 03:29 PM, Daniel Vetter wrote:
>>>> On Fri, Apr 24, 2015 at 06:07:05PM +0000, Konduru, Chandra wrote:
>>>>>
>>>>>
>>>>>> -----Original Message-----
>>>>>> From: Konduru, Chandra
>>>>>> Sent: Friday, April 24, 2015 10:53 AM
>>>>>> To: 'Tvrtko Ursulin'; Intel-gfx@lists.freedesktop.org
>>>>>> Cc: Ursulin, Tvrtko
>>>>>> Subject: RE: [PATCH] drm/i915/skl: Bypass debug message if scalers
>>>>>> are not
>>>>>> requested
>>>>>>
>>>>>>
>>>>>>
>>>>>>> -----Original Message-----
>>>>>>> From: Tvrtko Ursulin [mailto:tvrtko.ursulin@linux.intel.com]
>>>>>>> Sent: Friday, April 24, 2015 9:34 AM
>>>>>>> To: Konduru, Chandra; Intel-gfx@lists.freedesktop.org
>>>>>>> Cc: Ursulin, Tvrtko
>>>>>>> Subject: Re: [PATCH] drm/i915/skl: Bypass debug message if
>>>>>>> scalers are
>>>>>>> not requested
>>>>>>>
>>>>>>>
>>>>>>> On 04/24/2015 05:30 PM, Konduru, Chandra wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>> -----Original Message-----
>>>>>>>>> From: Tvrtko Ursulin [mailto:tvrtko.ursulin@linux.intel.com]
>>>>>>>>> Sent: Friday, April 24, 2015 9:08 AM
>>>>>>>>> To: Intel-gfx@lists.freedesktop.org
>>>>>>>>> Cc: Ursulin, Tvrtko; Konduru, Chandra
>>>>>>>>> Subject: [PATCH] drm/i915/skl: Bypass debug message if scalers are
>>>>>>>>> not requested
>>>>>>>>>
>>>>>>>>> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>>>>>>>>
>>>>>>>>> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>>>>>>>>> Cc: Chandra Konduru <chandra.konduru@intel.com>
>>>>>>>>> ---
>>>>>>>>> Up for discussion I suppose, but like it is, with typical
>>>>>>>>> drm.debug
>>>>>>>>> = 0xe, it logs one line per cursor movement while the log would
>>>>>>>>> otherwise be
>>>>>>> quiet.
>>>>>>>>> ---
>>>>>>>>>    drivers/gpu/drm/i915/intel_atomic.c | 3 +++
>>>>>>>>>    1 file changed, 3 insertions(+)
>>>>>>>>>
>>>>>>>>> diff --git a/drivers/gpu/drm/i915/intel_atomic.c
>>>>>>>>> b/drivers/gpu/drm/i915/intel_atomic.c
>>>>>>>>> index 3c4b7cd..7284c6d 100644
>>>>>>>>> --- a/drivers/gpu/drm/i915/intel_atomic.c
>>>>>>>>> +++ b/drivers/gpu/drm/i915/intel_atomic.c
>>>>>>>>> @@ -302,6 +302,9 @@ int intel_atomic_setup_scalers(struct
>>>>>>>>> drm_device
>>>>>>> *dev,
>>>>>>>>>        scaler_state = &crtc_state->scaler_state;
>>>>>>>>>        drm_state = crtc_state->base.state;
>>>>>>>>>
>>>>>>>>> +    if (!scaler_state->scaler_users)
>>>>>>>>> +        return 0;
>>>>>>>>
>>>>>>>> This will cause issue because scalers will never get freed if they
>>>>>>>> are in use
>>>>>>> before and no more required now.
>>>>>>>> I put the debug print to help debug variety of state related issues
>>>>>>>> while we are in development, but perhaps debug print can be
>>>>>>>> deleted.
>>>>>>>
>>>>>>> Doesn't the loop below skip everything anyway when no bits are
>>>>>>> set in
>>>>>>> scaler_state->scaler_users ?
>>>>>> Oh, that's right, ignore my prev comment (with updated scaler
>>>>>> design above
>>>>>> shouldn't cause issues).
>>>>>> By the way, can you pls run kms_panel_fit and kms_plane_scaling to
>>>>>> make sure
>>>>>> they pass and there are no related warnings or errors in kernel log?
>>>>>> For kms_plane_scaling, pls apply two pending patches that aren't
>>>>>> merged:
>>>>>> v5 [PATCH 13/14] drm/i915: skylake primary plane scaling using
>>>>>> shared scalers
>>>>>> v5 [PATCH 14/14] drm/i915: skylake sprite plane scaling using
>>>>>> shared scalers
>>>>>>
>>>>> One more: This change address logs when no scaler is required,
>>>>> but might comeback when a scaler is active (panel fitting or plane
>>>>> scaling is enabled).
>>>>> I don't know general policy in these kind of situations, but
>>>>> perhaps debug print
>>>>> can be deleted.
>>>>
>>>> Atomic is really complicated, but doing fully diagnostics for each
>>>> frame
>>>> is also way too noisy. For that reason we've add a DRM_DEBUG_ATOMIC
>>>> which
>>>> can be used for all these state tracking debug lines.
>>>
>>> We didn't do anything here and I just noticed kernel is still too spammy
>>> with regards to this issue.
>>>
>>> Should we just merge my patch? Still looks completely safe to me...
>>
>> doesn't seem to apply any more:(
>
> Yeah only some months have passed, who would have thought. :)
>
> But I realized that would be only one of the three log lines per cursor
> update - there is a code path calling skl_detach_scaler two times as
> well. Looks like this overall, per update:
>
> [drm:intel_atomic_setup_scalers] crtc_state = ffff880074b55c00 need = 0
> avail = 2 scaler_users = 0x0
> [drm:skl_detach_scaler] CRTC:21 Disabled scaler id 0.0
> [drm:skl_detach_scaler] CRTC:21 Disabled scaler id 0.1
>
> I'll rebase this patch for a start.

Sent it as a new thread but forgot v2 in the subject.

Other source of spam is probably intel_begin_crtc_commit -> 
skl_detach_scalers.

Don't know what the right fix would be there. Looks like it is not 
tracking transitions in scaler use so it would be able to act and log 
when something interesting happens, but rather does it every time. I 
defer to Chandra. :)

Regards,

Tvrtko
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