[Intel-gfx] [PATCH] drm/i915: Make __i915_printk debug output behave the same as DRM_DEBUG_DRIVER

[Imre Deak]

On ti, 2016-03-22 at 09:42 +0000, Chris Wilson wrote:
> On Mon, Mar 21, 2016 at 05:08:57PM +0200, Imre Deak wrote:
> > Joonas and Daniel remarked that our debugging output should stay
> > compatible
> > with the core DRM's debug facility. The recently added
> > __i915_printk() would
> > output debug messages even if debugging is completely disabled via
> > the
> > drm.debug option. To fix this make __i915_printk behave the same as
> > DRM_DEBUG_DRIVER in this case.
> > 
> > CC: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> > CC: Daniel Vetter <daniel.vetter at ffwll.ch>
> > CC: Chris Wilson <chris at chris-wilson.co.uk>
> > Signed-off-by: Imre Deak <imre.deak at intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_dma.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/i915_dma.c
> > b/drivers/gpu/drm/i915/i915_dma.c
> > index 3f439a0..a3458fc 100644
> > --- a/drivers/gpu/drm/i915/i915_dma.c
> > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > @@ -77,9 +77,13 @@ __i915_printk(struct drm_i915_private *dev_priv,
> > const char *level,
> >  	static bool shown_bug_once;
> >  	struct device *dev = dev_priv->dev->dev;
> >  	bool is_error = level[1] <= KERN_ERR[1];
> > +	bool is_debug = level[1] == KERN_DEBUG[1];
> >  	struct va_format vaf;
> >  	va_list args;
> >  
> > +	if (is_debug && !(drm_debug & DRM_UT_DRIVER))
> > +		return;
> 
> This feels overly restrictive for __i915_printk. It makes sense for
> report_error, but that is already KERN_ERR only.

It's also used by failure injection. But yes, I agree that in the
future a more generic mapping from DRM debug mask to dynamic debug
filtering could be used instead of this (also considered already by
Joonas and Daniel).

> From the point-of-view that we are documenting what needs to be done
> in
> future,
> Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>

Thanks,
Imre

> -Chris
>