From: Daniel Vetter <daniel@ffwll.ch>
To: Ben Widawsky <ben@bwidawsk.net>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915/bdw: Don't use forcewake needlessly
Date: Tue, 10 Dec 2013 23:30:10 +0100 [thread overview]
Message-ID: <20131210223010.GU9804@phenom.ffwll.local> (raw)
In-Reply-To: <20131210194716.GB27093@bwidawsk.net>
On Tue, Dec 10, 2013 at 11:47:17AM -0800, Ben Widawsky wrote:
> On Tue, Dec 10, 2013 at 03:24:52PM +0200, ville.syrjala@linux.intel.com wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Not all registers need forcewake even if they're not shadowed.
> > Add the missing NEEDS_FORCE_WAKE() check to gen8_writeX() to
> > avoid needless forcewake usage when writing eg. display
> > registers.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> > I didn't test this at all, so be warned.
> >
> > drivers/gpu/drm/i915/intel_uncore.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> > index e63658e..78fe8d6 100644
> > --- a/drivers/gpu/drm/i915/intel_uncore.c
> > +++ b/drivers/gpu/drm/i915/intel_uncore.c
> > @@ -616,7 +616,8 @@ static bool is_gen8_shadowed(struct drm_i915_private *dev_priv, u32 reg)
> > #define __gen8_write(x) \
> > static void \
> > gen8_write##x(struct drm_i915_private *dev_priv, off_t reg, u##x val, bool trace) { \
> > - bool __needs_put = !is_gen8_shadowed(dev_priv, reg); \
> > + bool __needs_put = NEEDS_FORCE_WAKE(dev_priv, reg) && \
> > + !is_gen8_shadowed(dev_priv, reg); \
> > REG_WRITE_HEADER; \
> > if (__needs_put) { \
> > dev_priv->uncore.funcs.force_wake_get(dev_priv, \
>
> I would prefer if this was simply checking the display offset, as
> opposed to NEEDS_FORCE_WAKE - since if someone adds to the macro we run
> the risk of a potentially hard to track down bug.
Yeah, I agree that an explicit check would be better since the forcewake
stuff works a bit different on gen8+
-Daniel
>
> In any case, the patch is functionally correct, and I'd prefer the
> change, but up to you:
> Reviewed-by: Ben Widawsky <ben@bwidawsk.net>
>
> > --
> > 1.8.3.2
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Ben Widawsky, Intel Open Source Technology Center
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@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
next prev parent reply other threads:[~2013-12-10 22:29 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-10 13:24 [PATCH] drm/i915/bdw: Don't use forcewake needlessly ville.syrjala
2013-12-10 19:47 ` Ben Widawsky
2013-12-10 22:30 ` Daniel Vetter [this message]
2013-12-13 11:26 ` [PATCH v2] " ville.syrjala
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