Re: [gentoo-user] Re: google-chrome can render pages after update

[Michael <confabulate@kintzios.com>]

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On Monday, 12 June 2023 17:57:47 BST Grant Edwards wrote:
> On 2023-06-12, Michael <confabulate@kintzios.com> wrote:
> >> It seems to be a variation on this bug which affects only AMD GPUs:
> >>     https://bugs.gentoo.org/907431
> >> 
> >> Clearing the GPU driver cache or using the
> >> -disable-gpu-driver-bug-workarounds option avoids the problem.
> >> 
> >> In my case, It wasn't a mesa update that triggered the problem. I
> >> think it was the llvm update (I haven't confirmed that).
> > 
> > Did you (re)compile anything graphics related using llvm, which
> > might be used by the Chrome binary?
> 
> No -- but as I understand it, mesa uses llvm (at runtime) to generate
> GPU object code. Based on the work-around, it looks like compiled GPU
> object code is cached by Chrome/Chromium, and updates to mesa and/or
> llvm can result attempts to use old, incompatible GPU object code.
> 
> As pages are rendered, there was a constant stream of "link failure"
> messages on the console window where Chrome is running.

Yes, you're right.  Gallium llvmpipe driver uses llvm in runtime for 
rasterisation.  I wasn't aware of this and thought llvm is only a build time 
compiler!  :-)  

This also explains why clearing the cache fixes the problem of what is 
essentially stale code.

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