[Paranoia] sg_write kernel logging flood

[Tobias Jakobi]

xiphmont at xiph.org wrote:
> Eg, the old interface (actually, lower layers) will often abort DMA
> early with no error message and hand back a buffer half full of
> garbage and claim successful completion.  The only way to get around
> that is to force-fill the transfer buffer with a known pattern first
> by abusing the transfer direction flag.  This is not 'ambiguous'.
> This is 'I'm forced to do absurd things to get simple transfers to
> work reliably'.  The interface authors and I agreed at the time this
> should be as upported behavior because it was way easier than fixing
> the rest of the kernel. Welcome to Linux.  Here's a party hat and some
> Chlorpram.
Is this problem with aborted transfers still existent? I'm only a normal
end-user but I'm surprised that such major bugs still exist...

>
> <flame target="not dgilbert">
>
> If some new maintainer decided that this was 'not cool' I hope they
> also bothered to implement DMA completion status reporting.
> Otherwise, whining about it in their
> Livejournal^H^H^H^H^H^H^H^H^Hkernel log is not going to solve the
> original problem of unreliable transfers.
>
> I'll note that brand spanking new SGIO *also* allows prefill of a DMA
> transfer buffer for exactly the reason I state above: Last I looked,
> most drivers are swallowing DMA errors and never reporting.  So I'm
> guessing SG3 is also still broken this way, and someone needs to go
> remove the idiot 'waaaah!  Stop touching me!' kernel log message.
>
> Or we could all just buy Macs.  I hear they can do simple transfers
>> from CDROM pretty well.
I hope that the switch to the new ATA layer increases the work done on
the SCSI code, maybe making this hacks obsolete.

> There's a new release that's on hold because it turns out using SGIO
> on SATA cdrom drives is a good way to panic the kernel.  I should
> release it anyway as 'incentive' for the kernel maintainers to 'fix'
> their 'code'.
>
> If you don't have a SATA cdrom, the cdparanoia10pre in SVN is fully up
> to date with the latest kernel interfaces in that it will prefer SGIO
> over SG.  If you force it to use SG, you will still get the whiny
> kernel log messages because the kernel log message is ill considered.
Good to know. If I have some spare time I'm going to test from SVN.
Maybe Gentoo should update their ebuild, especially since the latest
version in the portage tree is from 2001.

And I didn't mean to start some flame war, so be nice to each other : -)

Bye,
Tobias