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<body><span class="vcard"><a class="email" href="mailto:kenneth@whitecape.org" title="Kenneth Graunke <kenneth@whitecape.org>"> <span class="fn">Kenneth Graunke</span></a>
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<a class="bz_bug_link
bz_status_NEW "
title="NEW - glReadPixels on Intel N3700 (Braswell) slower than Raspberry Pi"
href="https://bugs.freedesktop.org/show_bug.cgi?id=99247">bug 99247</a>
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<td>jason@jlekstrand.net, kenneth@whitecape.org
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<b><a class="bz_bug_link
bz_status_NEW "
title="NEW - glReadPixels on Intel N3700 (Braswell) slower than Raspberry Pi"
href="https://bugs.freedesktop.org/show_bug.cgi?id=99247#c5">Comment # 5</a>
on <a class="bz_bug_link
bz_status_NEW "
title="NEW - glReadPixels on Intel N3700 (Braswell) slower than Raspberry Pi"
href="https://bugs.freedesktop.org/show_bug.cgi?id=99247">bug 99247</a>
from <span class="vcard"><a class="email" href="mailto:kenneth@whitecape.org" title="Kenneth Graunke <kenneth@whitecape.org>"> <span class="fn">Kenneth Graunke</span></a>
</span></b>
<pre>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?</pre>
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