Fwd: Indirect GLX still broken

[Ilya Anfimov]

On Tue, Jun 12, 2018 at 10:29:38AM +0100, Steve Dodd wrote:
>    On 12 June 2018 at 10:08, Ilya Anfimov <[1]ilan at tzirechnoy.com> wrote:
> 
>       No, currently there is no developers willing to improve this.
>       However, you can try some proxies like virtualgl.
> 
>    Is there any understanding of the root of the problem? In theory I could
>    start looking into it, but I'm old and ill and very out-of-date on modern
>    technologies like git :)

 Well,  the  code  was disabled when it was found a lot of buffer
overflows.
 Currently, it requires thorough analysis and fixing of security-
related weaknesses.
 Hoewer, it was easily droppped beacause it was barely usable:
  current  usage  patterns requires a lot of interactions with GL
subsystem, many of them transferring (or sometimes just  pointing
to) a huge amount of data, with some assumed synchronizations. It
was barely compatible with 20-year old code of sockets-based  in-
terprocess  comuncation.  The GLX pathway had too many data copy-
ing, that process wass too CPU-based and sycnhronous, also it had
some  optimisations  of  packing  and pipelining drawcalls in one
write() syscall, which was essential for performance but  created
awful buffering issues for unaware application and hardware.
(Like buffering data for 15 seconds of rendering. Not
exciting at all for gaming!)

 So, probably it can be enabled after security analysis, but have
to be reengineered after that to be useful.

>    I currently have quite a lot on my plate, but will at some point try roll
>    backing to earlier versions, etc. as has been done in the bug report.
>    Thanks for the virtualgl tip - it's possible that will be the fastest
>    solution anyway, but I was really hoping to be able to try all the options
>    and pick the best! I know there was a fuss a few years ago when IGLX was
>    disabled by default, as some in the scientific community were using it --
>    is that not still the case?
>    Steve
> 
> References
> 
>    Visible links
>    1. mailto:ilan at tzirechnoy.com

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