Yeah, seems like I at least missed EXT_texture_rg for allowing RG-textures:

Something like this should correct it:
---8<---
Author: Erik Faye-Lund <erik.faye-lund@collabora.com>
Date:   Tue Dec 4 12:34:39 2018 +0100

    mesa/main: fix up _mesa_has_rg_textures for gles2
    
    rg-textures are supported in GLES 2.0 if EXT_texture_rg, so let's make
    sure the enums are accepted.
    
    Fixes: 510b6424607 "mesa/main: do not allow rg-textures enums before gles3"
    Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>

diff --git a/src/mesa/main/context.h b/src/mesa/main/context.h
index cdda8cf2012..7de10e9924b 100644
--- a/src/mesa/main/context.h
+++ b/src/mesa/main/context.h
@@ -378,7 +378,8 @@ _mesa_has_packed_float(const struct gl_context *ctx)
 static inline bool
 _mesa_has_rg_textures(const struct gl_context *ctx)
 {
-   return _mesa_has_ARB_texture_rg(ctx) || _mesa_is_gles3(ctx);
+   return _mesa_has_ARB_texture_rg(ctx) || _mesa_has_EXT_texture_rg(ctx) ||
+          _mesa_is_gles3(ctx);
 }
 
 static inline bool
---8<---


dEQP-GLES2.functional.fbo.completeness.renderable.texture.stencil.sr8_ext seems to be something else, but this is a brand new extension that isn't written against GLES 2 in the first place, so in that case it seems c4136ed5cc07a73c01d24a1c17ebe71e2690aef7 did exactly what it was supposed to, and the test is incorrect... also, I can't find such a test under the gles2 module in dEQP, only under gles3. What's up? :P

I'm also not really sure about those two piglit tests... Perhaps the planar extensions depend on rg-textures somehow? If so, perhaps the patch above fixes it, but we might have similar issues for GLES 1.x...

All test failures bisected to:
510b6424607b1e8af96162f6d571de34beb89e86
Author:     Erik Faye-Lund <erik.faye-lund@collabora.com>

mesa/main: do not allow rg-textures enums before gles3

EXT_packed_float isn't supported on OpenGL ES, we shouldn't allow
these enums there, before OpenGL ES 3.0 which also introduce support
for these enums.

Since this check is repeated a lot, let's make a helper for this.

Signed-off-by: Erik Faye-Lund <erik.faye-lund@collabora.com>
Reviewed-by: Marek Olšák <marek.olsak@amd.com>


I'll test the proposed fix.

Should be fixed by 91af56e3835bbc17f5b110ac472724cd0986503c