[Mesa-dev] [PATCH] dri_util: fallback to core with drivers not supporting compat for 3.1

[Emil Velikov]

Hi Andres,

On 2 March 2018 at 22:55, Andres Gomez <agomez at igalia.com> wrote:
> 2599b92eb97 changed Mesa's behavior to allow Compatiblity profile with
> 3.1, and fail when the driver doesn't implement it, if the Core
> profile is not requested by applications.
>
> Formerly, when requesting a 3.1 Compatibility profile Mesa would
> always fall back into a Core profile. We go back to that behavior now
> so, if the specific driver is not supporting 3.1 with Compatibility
> profile, we will keep falling back into 3.1 Core.
>
The above message seems pretty hard to parse. May I suggest reusing
the inline comment as commit message, or borrowing something like
below:

---
Currently, the i965 driver does not support the ARB_compatibility
extension, thus creating an GL3.1 context (which is implicitly a
compat one) will fail.
Props to the validate_context_version() check and i965's
"max_gl_compat_version = 30"

Restore the original check which changes mesa_api to API_OPENGL_CODE, only when:
 - GL3.1 + API_OPENGL_COMPAT is requested, and
 - driver does not support ARB_compatibility - as deduced by
max_gl_compat_version
---

\The 2599b92eb97 hunk seems misplaced bth, so I'd drop it all together.

With that the patch is
Reviewed-by: Emil Velikov <emil.velikov at collabora.com>

Orthogonal to that, it might be a good idea to:
 - split the ARB_compatibility hunk out of _mesa_compute_version -
only st/mesa should do it + it seems misplaced all together
 - add GL3.1 compat support for i965

-Emil