[PATCH libdrm] intel: annotate the intel genx helpers as private

[Chih-Wei Huang]

2018-09-20 7:18 GMT+08:00 Lucas De Marchi <lucas.demarchi at intel.com>:
> On Wed, Sep 19, 2018 at 03:47:48PM +0800, Chih-Wei Huang wrote:
>> 2018-09-14 2:23 GMT+08:00 Lucas De Marchi <lucas.demarchi at intel.com>:
>> > +Chris
>> >>
>> >> That's because drm_gralloc use the IS_GEN9 macro
>> >> (and other IS_GEN{n} macros) directly.
>> >>
>> >> Since IS_GEN{n} are public APIs, I don't see
>> >
>> >
>> > IS_GEN() is *not* public API and should not be. It's an internal macro.
>> >
>> > DESTDIR=/tmp/inst ninja -C build install
>> > grep -r IS_GEN /tmp/inst/
>> > Binary file /tmp/inst/usr/local/lib64/libdrm_intel.so.1.0.0 matches
>> >
>> >   [  same thing when using autotools ]
>> >
>> > Grepping https://android.googlesource.com/platform/external/drm_gralloc/ I
>> > see IS_GEN* is being used, but I don't see where it's getting it from,
>> > unless it's using private headers... Let's see by grepping it:
>> >
>> > $ git grep intel_chipset
>> > gralloc_drm_intel.c:#include "intel_chipset.h" /* for platform detection
>> > macros */
>> >
>> > oh. You're a using a private header :(. How many places and libraries will
>> > we need to update to support different platforms? This is crazy.
>> > AFAICS it only uses that to get the max_stride for each platform... this
>> > info should be coming from somewhere else. Chris, any idea here?
>>
>> Hmm... There is no private declaration in this header.
>
> ???
>
>> Why is it private?
>
> All headers are private unless they are exported/installed. Android does
> things a little differently by incorporating libdrm inside this drm_gralloc.
>
>> If so, what is the correct way to get the gen of Intel's GPU?
>> Or the userspace should not know it?
>
> libdrm *is* userspace.

Sorry.
I meant an app which uses libdrm.
Shouldn't the app know the gen?

One interesting I just found.
I noticed Mesa has its own intel_chipset.h
which defines the IS_GEN3 macro.
(~src/mesa/drivers/dri/i915/intel_chipset.h)

So... to get the gen, I need to write my own header?
Or just copy libdrm's header?

> Better question: why do you need to know the gen? Can
> this be decided in another way by using a properly exported function from
> libdrm?

OK. That's another question.
The simple answer is I don't know.
That code is not written by me.
The code was written by some Google and Intel engineers.
So Intel engineer didn't think that header is private,
at least at that time he wrote the code...

> If you only want to hack it to work again, just link with the static library
> since you are already incorporating the library, as Chris suggested. If you
> want to do it right you may need to look into your library to see why it
> is doing that.