[Mesa-dev] [PATCH] util/disk_cache: Fix disk_cache_get_function_timestamp with disabled cache.

[Bas Nieuwenhuizen]

On Thu, Jul 26, 2018 at 5:01 PM, Emil Velikov <emil.l.velikov at gmail.com> wrote:
> Hi Bas,
>
> Pardon for joining so late.
>
> On 18 July 2018 at 13:01, Bas Nieuwenhuizen <bas at basnieuwenhuizen.nl> wrote:
>> radv always needs it, so just check the header instead. Also
>> do not declare the function if the variable is not set, so we
>> get a nice compile error instead of failing to open a device
>> at runtime.
>>
> AFAICT the ENABLE_SHADER_CACHE define is set on all POSIX platforms.
> Back in the early days we had --enable-shader-cache which was removed
> with d1efa09d342bff3e5def2978a0bef748d74f9c82
>
> Apart from the reasons listed, we do not want to control this at
> configure time since it will produce varying driver behaviour. Hence
> multiple unhappy users, as they hit the codepath w/o cache.
>
> Skimming through - I would imagine you're building with meson, which
> has the explicit shader cache toggle.
> I'm assuming Dylan had it based on early autconf builds?
>
> We can drop that one and effectively revert this and the follow-up Android fix.
>
> What do you think?

ChromeOS disables it for reasons I'm currently not sure about:

https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/mesa/mesa-18.2_pre1.ebuild#197

And since the primary use case for vulkan at the moment seems to be
Android and I can conceive us not being able to use the cache there
for reasons, I'm not sure if disabling the cache is really that
unreasonable, though it is not ideal that they apparently override the
upstream configure.

Since most of that stuff seems to be driven by GL, this is pretty much
a "isolate radv from whatever people do on the GL side of things"
patch.

> Emil