Re: [PATCH 4/4] drm/i915: Drop WaIncreaseLatencyIPCEnabled/1140 for cnl

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Mon, Feb 04, 2019 at 09:49:42AM -0800, Rodrigo Vivi wrote:
> On Mon, Feb 04, 2019 at 07:40:56PM +0200, Ville Syrjälä wrote:
> > On Thu, Jan 31, 2019 at 10:10:47AM -0800, Rodrigo Vivi wrote:
> > > On Thu, Jan 31, 2019 at 09:42:16AM +0200, Ville Syrjala wrote:
> > > > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > 
> > > > Drop WaIncreaseLatencyIPCEnabled/Display w/a #1140 for
> > > > early cnl steppings. Also switch the kbl/cfl case to check
> > > > for IS_GEN9_BC() for brevity. It ends up being the same thing
> > > > because IPC is disabled on SKL due to w/a #0477.
> > > 
> > > I think this deserves a commend in the code, otherwise someone
> > > in the future might not notice that and send a patch to replace
> > > 9_BC per KBL || CFL...
> > > 
> > > anyway:
> > > 
> > > Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > 
> > Ta. I just noticed there were some other IS_KBL||IS_CFL cases in the
> > code as well. So maybe I'll just leave it as is here too.
> > 
> > One thing I don't like is that w/a #0477 is in the device info. I think
> > I'll want to move that into ipc code to make it less confusing what's
> > going on.
> 
> 
> yeap, I think it makes more sense to have the wa inside ipc code rather
> than inside device info. But on the other hand it gets confuse if we
> end up reading has_ipc=1 and then we have to go inside ipc to find
> out that actually has_ipc is lying :/

It's not really lying though. The hw has it, we're just not supposed
to use it.

> 
> > 
> > > 
> > > 
> > > 
> > > > 
> > > > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_pm.c | 4 +---
> > > >  1 file changed, 1 insertion(+), 3 deletions(-)
> > > > 
> > > > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > > > index 306e41ccc50e..55491e2d5134 100644
> > > > --- a/drivers/gpu/drm/i915/intel_pm.c
> > > > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > > > @@ -4701,9 +4701,7 @@ static void skl_compute_plane_wm(const struct intel_crtc_state *cstate,
> > > >  	 * WaIncreaseLatencyIPCEnabled: kbl,cfl
> > > >  	 * Display WA #1141: kbl,cfl
> > > >  	 */
> > > > -	if ((IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv) ||
> > > > -	    IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_B0)) &&
> > > > -	    dev_priv->ipc_enabled)
> > > > +	if (IS_GEN9_BC(dev_priv) && dev_priv->ipc_enabled)
> > > >  		latency += 4;
> > > >  
> > > >  	if (skl_needs_memory_bw_wa(dev_priv) && wp->x_tiled)
> > > > -- 
> > > > 2.19.2
> > > > 
> > > > _______________________________________________
> > > > Intel-gfx mailing list
> > > > Intel-gfx@lists.freedesktop.org
> > > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx
> > 
> > -- 
> > Ville Syrjälä
> > Intel
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > https://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel
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