Re: IrDA driver fails on PXA255

[David Rientjes]

On Sun, 29 May 2011, Russell King - ARM Linux wrote:

> > That would return memory that is not guaranteed to be within the first 
> > 16MB of address space, so a GFP_DMA allocation would succeed with memory 
> > not from ZONE_DMA.
> 
> Err, no. GFP_DMA returns memory in a zone which the platform has setup.
> There's nothing specific about it being "16MB" or any other size; the
> arch can chose what size that is.
> 

Sorry, was talking from the x86 perspective, which probably doesn't make 
much sense since we're talking about an arm driver :)

> > That's an invalid configuration, so users, including 
> > you, should at least edit their .config by hand to enable CONFIG_ZONE_DMA 
> > as a workaround.
> 
> Again, no.  This change has caused a load of previously working drivers
> to suddenly start failing without _any_ explanation why or even warning
> about the change.  It needs to start off as a WARN_ON() so that stuff
> can be fixed, and then changed to a hard error.
> 

I haven't seen a "load" of error reports where this is causing an issue, 
maybe it is much more popular on arm?

This also isn't a hard error, admins should be able to enable 
CONFIG_ZONE_DMA and rebuild so that the driver being loaded can get the 
type of memory it is requesting.  Just putting a WARN_ON() doesn't provide 
any incentive to ever get this stuff fixed.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/