Re: IrDA driver fails on PXA255

From: Russell King - ARM Linux
Date: Tue May 31 2011 - 03:27:16 EST


On Mon, May 30, 2011 at 10:05:38PM -0700, David Rientjes wrote:
> On Sun, 29 May 2011, Russell King - ARM Linux wrote:
> > 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.

I completely and violently disagree with your approach on this, and I'll
continue to state that I believe you are wrong until you change your
position.

Enabling CONFIG_ZONE_DMA is not a fix, it's making the problem vanish off
the radar. It will mean that the drivers using GFP_DMA will never get
fixed up.

I don't care whether you say "it's easy enough to audit the source code" -
who's going to do that work? If you make the problem go away the answer
to that will be NO ONE.

Change it to be a soft WARN_ON for one release. Anything else will just
result in the problem being IGNORED.
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