[Intel-gfx] [PATCH 4/7] drm/i915/icl: Add Voltage swing table for MG PHY DDI Buffer

[Chris Wilson]

Quoting Paulo Zanoni (2018-04-10 21:39:31)
> Em Ter, 2018-04-10 às 09:51 +0100, Chris Wilson escreveu:
> > Quoting Paulo Zanoni (2018-03-23 17:24:16)
> > > From: Manasi Navare <manasi.d.navare at intel.com>
> > > 
> > > This table is used for voltage swing programming sequence during
> > > DDI
> > > Buffer initialization for MG PHY DDI Buffers on Icelake.
> > 
> > Except it is not used at all...
> 
> It's going to be used later in the series.
> 
> > 
> > drivers/gpu/drm/i915/intel_ddi.c:601:46: error:
> > ‘icl_mg_phy_ddi_translations’ defined but not used [-Werror=unused-
> > const-variable=]
> 
> I have all of the I915 debugging options enabled, including
> CONFIG_DRM_I915_WERROR=y, and I don't get this error. I'm using Fedora
> 27's gcc. Would it be the case that you have somehow enabled the
> unused-const-variable warning through some non-traditional way that's
> not upstream?

Try make W=1 (which includes kerneldoc checks!). Or clang (don't try
clang unless you are a masochist, especially not right now as -Wvla
upsets it).
 
> If that's the case, and if we decide that we want Werror=unused-const-
> variable to block patches from being merged, then I think we should put
> this error/warning under the i915 debugging .config options and force
> CI to also use them and tell us about them.

I'm trying to get W=1 as part of the pre-merge warning set, at the same
level of severity as ignoring checkpatch.
 
> Because I'm pretty sure if we start enabling random gcc warning/error
> flags we'll be able to block a huge number of patches from being
> upstreamed. I just don't think this is something we should do.

We do. Our code is clean at W=1 except for the odd mistake. Let's keep
it that way. As new gcc warnings are developed, we will squash petty
nuisances and sometimes outright bugs from the code (it has happened
before and will happen again).
-Chris