On 02/18/2016 08:19 PM, Emil Velikov wrote:
Hi guys,
On 15 February 2016 at 10:54, Tapani Pälli <[email protected]> wrote:
From: Daniel Czarnowski <[email protected]>
Patch provides a 'sane default' for a set pbuffer surface size when
Perhaps too cheeky of a question but "who is to determine these 'sane
defaults'" ?
I agree this is not ideal but it's a lot better than complete failure?
The default set in the patch is quite conservative. We could have a
driver hook but I'm not convinced it's worth it in this particular case,
again this is really a case for robustness testing, not for a real life
application.
If those are OK for one hardware/generation they won't be for another.
I believe the whole problem boils down to the fact that we don't do
anything in case of EGL_LARGEST_PBUFFER. Looking at GLX -
GLX_LARGEST_PBUFFER seems to be in the same boat :-\
Imho one should honour it while creating the surface. Afaics the spec
isn't clear if height/width should be ignored when the bool is set (or
I missed that hunk), so I'm leaning towards "yes".
The spec is "if we can't allocate the size what is requested we allocate
max possible size":
"Use EGL_LARGEST_PBUFFER to get the largest available pbuffer when the
allocation of the pbuffer would otherwise fail."
So we would try to allocate what is requested but we have a limit that
says it will fail so let's not. IIRC X driver has 32k for max pixmap
size but as they are textures nowadays in practice this limit will be
much smaller.
EGL_LARGEST_PBUFFER is used by the client. MIN2 macro is moved to
egldefines so that it can be shared.
Fixes following Piglit test:
egl-create-largest-pbuffer-surface
With the above said, I'm not sure how much sense it makes to have
explicit EGL_HEIGHT/WIDTH in the test, alongside EGL_LARGEST_PBUFFER
in the mentioned test.
In all fairness, fixing this properly might result in a serious
(series of) patch(es). Which might be a bit too much for stable ?
Better to cross that road as we reach it :-)
I did some investigation and it seems currently there is no way to query
maximum size of a pixmap using xlib or xcb, only way would be to try
this in a loop. Xcb uses uint16_t type so you could determine it from
that but with most (all?) drivers it would fail with max.
// Tapani
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