Re: CVS commit: src/sys

[Tetsuya Isaki <isaki%pastel-flower.jp@localhost>]

At Fri, 3 Apr 2020 15:15:36 +0200,
Martin Husemann wrote:
> >  [*] On my alpha (500MHz), wss(4)/ISA works even on blk_ms=1.
> >  But I was not able to set 1msec on yds(4) PCI sound card on
> >  the same machine.  Its lower limit was 5msec (due to driver's
> >  or hardware's restriction, I don't know details though).
> 
> Should we allow the driver to set a lower minimum for this?

(sorry if I misunderstood your text.)
I don't think so.  Each driver/hardware may have their specific
restrictions.  Some driver/hardware may be able to set at 1msec
but others may not.  It's nature.  And this is also why we
should not be eager to reduce default blk_ms.

> Then all m68k and vax drivers could just request (say) 100ms and we are 
> done?

I don't think so.  It breaks MI/MD separation (though the most
drivers on m68k/vax are port-specific).
It's better to handle separately "how long default blk_ms is
better?" and "blocksize driver/hardware supports".

Thanks,
---
Tetsuya Isaki <isaki%pastel-flower.jp@localhost / isaki%NetBSD.org@localhost>