[Mesa-dev] [PATCH 13/16] anv/image: Add support for modifiers for WSI

[Daniel Stone]

On 14 February 2018 at 16:21, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Wed, Feb 14, 2018 at 4:13 AM, Daniel Stone <daniel at fooishbar.org> wrote:
>> Suggested fixup: https://hastebin.com/zaheyoriwa
>>
>> This makes sure we only try to allocate with modifiers when _both_
>> winsys and driver support it.
>
> Ok, we clearly have different philosophies here so we should get that
> sorted.  My philosophy is that the winsys code will look at the
> wsi_device::supports_modifiers flag and not ask for modifiers if it's false.
> You seem to think that the winsys code should just go ahead and ask for
> modifiers all the time and we will try to deal with it in wsi_create_native.
> Thoughts?  Arguments?  Strong opinions?
>
> If we keep my philosophy, we should add asserts to better document and
> enforce it.

Yeah, it was mostly based on missing the wsi->has_modifiers check in
the Wayland code, and it being totally absent in the X11/DRI3 code
(trivial to add). So my philosophy was mostly about avoiding asserts,
rather than strong feelings about who should do the filtering.

I'm happy to stick with how you have it, plus asserts. Thanks for the
explanation!

Cheers,
Daniel