[Buildroot] [PATCH RESEND 0/2] Use bzip2 for X11 PFC font compression
thomas.petazzoni at bootlin.com
Mon Jul 13 19:56:41 UTC 2020
On Mon, 13 Jul 2020 14:55:10 -0500 (CDT)
Aaron Sierra <asierra at xes-inc.com> wrote:
> >> 1. Even with the latest gzip, these seemingly synonymous pipelines
> >> produce different output, but this issue does not exist with bzip2:
> >> $ cat /path/to/file | gzip > /path/to/file.gz
> >> $ gzip < /path/to/file > /path/to/file.gz
> >> 2. Prior to gzip 1.10, the compression pipeline used with PCF fonts was
> >> not reproducible due to the implicit -N/--name injecting a timestamp:
> >> * cat /path/to/file | gzip > /path/to/file.gz
> >> 3. The BR2_USE_WCHAR dependency of the gzip package tarnishes the appeal
> >> of using host-gzip to provide reproducible output.
> > This argument seems pretty weird. The fact that gzip needs
> > BR2_USE_WCHAR on the target doesn't at all prevent from building
> > host-gzip. We have plenty of host packages that need wchar packages,
> > and we simply assume the host system as wide char support available.
> > So this third argument is a bit "moot", especially since
> > host-xapp-mkfontscale already has a dependency on host-gzip, which
> > builds a gzip 1.10, so it shouldn't be affected by the problem you
> > describe.
> OK, then maybe adding a host-gzip dependency would be the better solution.
> I've found some evidence that this patchset isn't complete with respect to
> X itself using bzip-compressed fonts :(
> > So that leaves us with just argument (1), correct ?
> Well, I think that (2) or (3) would be needed as the real justification for
> switching compression mechanisms. Let me investigate the host-gzip path now
> that I know that isn't a compatibility problem.
Thomas Petazzoni, CTO, Bootlin
Embedded Linux and Kernel engineering
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