[Mesa-dev] [PATCH 1/4] util: Add a drm_find_modifier helper

[Rob Clark]

On Thu, Mar 14, 2019 at 5:51 AM Eric Engestrom <eric.engestrom at intel.com> wrote:
>
> On Thursday, 2019-03-14 04:19:02 +0000, Alyssa Rosenzweig wrote:
> > This function is replicated across vc4/v3d/freedreno and is needed in
> > Panfrost; let's make this shared code.
> >
> > Signed-off-by: Alyssa Rosenzweig <alyssa at rosenzweig.io>
> > ---
> >  src/util/u_drm.h | 46 ++++++++++++++++++++++++++++++++++++++++++++++
> >  1 file changed, 46 insertions(+)
> >  create mode 100644 src/util/u_drm.h
> >
> > diff --git a/src/util/u_drm.h b/src/util/u_drm.h
> > new file mode 100644
> > index 00000000000..d543c9a7543
> > --- /dev/null
> > +++ b/src/util/u_drm.h
> > @@ -0,0 +1,46 @@
> > +/*
> > + * Copyright © 2014 Broadcom
> > + * Copyright (C) 2012 Rob Clark <robclark at freedesktop.org>
> > + *
> > + * Permission is hereby granted, free of charge, to any person obtaining a
> > + * copy of this software and associated documentation files (the "Software"),
> > + * to deal in the Software without restriction, including without limitation
> > + * the rights to use, copy, modify, merge, publish, distribute, sublicense,
> > + * and/or sell copies of the Software, and to permit persons to whom the
> > + * Software is furnished to do so, subject to the following conditions:
> > + *
> > + * The above copyright notice and this permission notice (including the next
> > + * paragraph) shall be included in all copies or substantial portions of the
> > + * Software.
> > + *
> > + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> > + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> > + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
> > + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> > + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
> > + * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
> > + * IN THE SOFTWARE.
> > + */
> > +
> > +#ifndef U_DRM_H
> > +#define U_DRM_H
> > +
> > +#include <stdint.h>
> > +
> > +/* Given a list of `count` DRM modifiers `haystack` and a desired modifier
> > + * `needle`, returns whether the modifier is found */
> > +
> > +static bool
> > +drm_find_modifier(uint64_t needle, const uint64_t *haystack, unsigned count)
> > +{
> > +        unsigned i;
> > +
> > +        for (i = 0; i < count; i++) {
> > +                if (haystack[i] == needle)
> > +                        return true;
> > +        }
> > +
> > +        return false;
> > +}
>
> This is an extremely generic loop; it has nothing to do with modifiers,
> they just happen to be uint64_t.
>
> Can we call it something like this?
>   static inline bool
>   array_contains_u64(uint64_t *array, size_t array_size, uint64_t needle)
>
> There could be other places that could use this function (or its
> u32/s64/s32 equivalents), there's no reason to prevent its adoption with
> a too specific name :)

hmm, I guess there are already two or three other places that already
copy/pasta'd this specifically for modifiers.. so I'm ok with the less
generic name, since it (IMHO) makes the code calling it more clear.

If there are other spots that need to search an array of other u64's,
then we could always do something like:

static inline bool
drm_find_modifier(...)
{
   return array_contains_u64(...);
}

seems a bit overkill..

Either way, w/ missing inline fixed, r-b

BR,
-R

>
> With a generic name (and the missing `inline` Christian also mentioned),
> the series is:
> Reviewed-by: Eric Engestrom <eric.engestrom at intel.com>
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