[Openpvrsgx-devgroup] Building Mesa for PVR

[Jonathan Bakker]

After finding some patches relating to PowerVR and Mesa on the Chromium git [1] I
started playing around with them to figure out if they would be useful for the SGX5
series (they're for the later versions).  It turns out that they can be used with the
DDK 1.17 blobs.  I've rebased the patches on Mesa 20.3 and placed them on my git repo
at https://github.com/xc-racer99/mesa-pvr/  There additionally needs to be a patch
to load the pvr_dri.so lib.  The patches don't include pvrsrvinit nor the core OpenGL
ES libraries, only the glue code around them.

I've verified that the ti443x blobs on s5pv210 (with the hex edit) work properly with
wlroots-based compositors when wlroots is patched for no ext unpack subimage extension
(as in the patch at [2]).  X-based distros don't appear to work with glamor/modesetting
due to limitations in it with respect to OpenGL ES backend and some PowerVR bugs.  The
Maemo Leste guys are working on this and trying to get something stable.

Do we have a full reference of what powervr.ini params are supported?  There appear to
be a number floating around, running strings on libGLESv2_PVR_MESA.so.1.17.4948957
(for ti443x) brings up a seeming list of strings that are related:

ExternalZBufferMode
FBODepthDiscard
OptimisedValidation
DisableHWTQTextureUpload
DisableHWTQNormalBlit
DisableHWTQBufferBlit
DisableHWTQMipGen
DisableHWTextureUpload
DisableHWTQTextureReadBack
FlushBehaviour
EnableStaticMTECopy
AdjustShaderPrecision
DumpCompilerLogFiles
DefaultVertexBufferSize
MaxVertexBufferSize
DefaultIndexBufferSize
DefaultPDSVertBufferSize
DefaultVDMBufferSize
DefaultPregenMTECopyBufferSize
StrictBinaryVersionComparison
PolygonUnitsMultiplier
PolygonFactorMultiplier
MaxGhostedBOMem
KickTAMode
KickTAThreshold
OverloadTexLayout
InitialiseVSOutputs
AllowTrilinearNPOT
EnableVaryingPrecisionOpt
EnableRecompileOpt

But most of these aren't in the OMAP wiki that I can find.

Hopefully this info is useful to someone.

Thanks,
Jonathan


[1] https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/media-libs/arc-mesa-img/files
[2] https://gitlab.com/postmarketOS/pmaports/-/issues/932#note_477113522