[Intel-gfx] [PATCH 02/16] drm/i915: fix the FBC work allocation failure path

[Paulo Zanoni]

2015-08-28 11:20 GMT-03:00 Ville Syrjälä <ville.syrjala at linux.intel.com>:
> On Fri, Aug 14, 2015 at 06:34:07PM -0300, Paulo Zanoni wrote:
>> Always update the currrent crtc, fb and vertical offset after calling
>> enable_fbc. We were forgetting to do so along the failure paths when
>> enabling fbc synchronously. Fix this with a new helper to enable_fbc()
>> and update the state simultaneously.
>>
>> v2: Improve commit message (Chris).
>>
>> Signed-off-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
>> ---
>>  drivers/gpu/drm/i915/intel_fbc.c | 27 +++++++++++++++++----------
>>  1 file changed, 17 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
>> index c97aba2..fa9b004 100644
>> --- a/drivers/gpu/drm/i915/intel_fbc.c
>> +++ b/drivers/gpu/drm/i915/intel_fbc.c
>> @@ -308,6 +308,18 @@ bool intel_fbc_enabled(struct drm_i915_private *dev_priv)
>>       return dev_priv->fbc.enabled;
>>  }
>>
>> +static void intel_fbc_enable(struct intel_crtc *crtc,
>> +                          struct drm_framebuffer *fb)
>
> fb could be const

I guess a lot of things could be constified, if we decide to do this.

>
>> +{
>> +     struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
>> +
>> +     dev_priv->fbc.enable_fbc(crtc);
>> +
>> +     dev_priv->fbc.crtc = crtc;
>> +     dev_priv->fbc.fb_id = fb->base.id;
>> +     dev_priv->fbc.y = crtc->base.y;
>> +}
>> +
>>  static void intel_fbc_work_fn(struct work_struct *__work)
>>  {
>>       struct intel_fbc_work *work =
>> @@ -321,13 +333,8 @@ static void intel_fbc_work_fn(struct work_struct *__work)
>>               /* Double check that we haven't switched fb without cancelling
>>                * the prior work.
>>                */
>> -             if (crtc_fb == work->fb) {
>> -                     dev_priv->fbc.enable_fbc(work->crtc);
>> -
>> -                     dev_priv->fbc.crtc = work->crtc;
>> -                     dev_priv->fbc.fb_id = crtc_fb->base.id;
>> -                     dev_priv->fbc.y = work->crtc->base.y;
>> -             }
>> +             if (crtc_fb == work->fb)
>> +                     intel_fbc_enable(work->crtc, work->fb);
>
> The no locking or refcounts nature of this scares me, and should be
> dealt with eventually.
>
> But in the meantime it makes things nicer, so
> Reviewed-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
>>
>>               dev_priv->fbc.fbc_work = NULL;
>>       }
>> @@ -361,7 +368,7 @@ static void intel_fbc_cancel_work(struct drm_i915_private *dev_priv)
>>       dev_priv->fbc.fbc_work = NULL;
>>  }
>>
>> -static void intel_fbc_enable(struct intel_crtc *crtc)
>> +static void intel_fbc_schedule_enable(struct intel_crtc *crtc)
>>  {
>>       struct intel_fbc_work *work;
>>       struct drm_i915_private *dev_priv = crtc->base.dev->dev_private;
>> @@ -373,7 +380,7 @@ static void intel_fbc_enable(struct intel_crtc *crtc)
>>       work = kzalloc(sizeof(*work), GFP_KERNEL);
>>       if (work == NULL) {
>>               DRM_ERROR("Failed to allocate FBC work structure\n");
>> -             dev_priv->fbc.enable_fbc(crtc);
>> +             intel_fbc_enable(crtc, crtc->base.primary->fb);
>>               return;
>>       }
>
> BTW getting rid of this allocation would be nice. Would be one less
> thing that can fail...

Chris disagrees :)


>
>>
>> @@ -826,7 +833,7 @@ static void __intel_fbc_update(struct drm_i915_private *dev_priv)
>>               __intel_fbc_disable(dev_priv);
>>       }
>>
>> -     intel_fbc_enable(intel_crtc);
>> +     intel_fbc_schedule_enable(intel_crtc);
>>       dev_priv->fbc.no_fbc_reason = FBC_OK;
>>       return;
>>
>> --
>> 2.4.6
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Ville Syrjälä
> Intel OTC
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> Intel-gfx at lists.freedesktop.org
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-- 
Paulo Zanoni