RE: [PATCH 4/4] DSS2: clear spurious SYNC_LOST_DIGIT interrupts

Tomi Valkeinen
2010-03-05T15:25:37Z

On Fri, 2010-03-05 at 16:19 +0100, ext Aguirre, Sergio wrote:
> Hi Ville,
>
> > -----Original Message-----
> > From: linux-omap-owner@vger.kernel.org [mailto:linux-omap-
> > owner@vger.kernel.org] On Behalf Of ville.syrjala@nokia.com
> > Sent: Friday, March 05, 2010 7:26 AM
> > To: Tomi Valkeinen
> > Cc: linux-fbdev@vger.kernel.org; linux-omap@vger.kernel.org; Ville Syrjälä
> > Subject: [PATCH 4/4] DSS2: clear spurious SYNC_LOST_DIGIT interrupts
> >
> > From: Ville Syrjälä <ville.syrjala@nokia.com>
> >
> > When DSS transitions from off mode to on VENC may generate a spurious
> > SYNC_LOST_DIGIT error. Just ack it when restoring the context. Also
> > restore IRQENABLE last to avoid triggering interrupts before the
> > context is fully restored.
>
> (Tomi or anyone can correct me if I'm wrong)
>
> AFAIK, The solution for spurious interrupts is to flush posted bus writes during interrupt handling, which can be achieved by reading the same register just after you have written it.
>
> Tomi, what do you think?

That's a different spurious interrupt =).

In this case the IRQ mechanism from CPU side is working fine, but VENC
is just spamming the error interrupts, for unknown reason.

Tomi