[Bug 99247] glReadPixels on Intel N3700 (Braswell) slower than Raspberry Pi

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=99247

Kenneth Graunke <kenneth at whitecape.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jason at jlekstrand.net,
                   |                            |kenneth at whitecape.org

--- Comment #5 from Kenneth Graunke <kenneth at whitecape.org> ---
In this case, _mesa_meta_pbo_GetTexSubImage is failing to handle this because
it doesn't believe it can create a texture of format MESA_FORMAT_RGB_UNORM8. 
That means that it falls back to CPU mapping, which is stalling.

We don't advertise texturing support for MESA_FORMAT_RGB_UNORM8 (or any other
3-component 8/16-bit formats) because we can't render to them.  Not supporting
those makes Mesa fall back to 4-component XRGB, which is renderable.  Normally,
this allow us to do more on the GPU.

I think Jason has some hacks for dealing with 3-component formats we might be
able to use.  (Vulkan doesn't play well with CPU fallbacks so he had to
implement a bunch of stuff.)  We might also be able to use typed surface
messages.

Jason, any thoughts on getting competent GPU PBO GetTexSubImage here?

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are the assignee for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-3d-bugs/attachments/20170108/a29813c1/attachment.html>