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

Aguirre, Sergio
2010-03-05T15:28:48Z

> -----Original Message-----
> From: Tomi Valkeinen [mailto:tomi.valkeinen@nokia.com]
> Sent: Friday, March 05, 2010 9:25 AM
> To: Aguirre, Sergio
> Cc: Syrjala Ville (Nokia-D/Helsinki); linux-fbdev@vger.kernel.org; linux-
> omap@vger.kernel.org
> Subject: RE: [PATCH 4/4] DSS2: clear spurious SYNC_LOST_DIGIT interrupts
>
> 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.

Ohh ok, I see.

Thanks for clarifying. And sorry for the noise.

I'm trying to learn about DSS subsystem, but I'm just a n00b for the moment :)

Regards,
Sergio
>
> Tomi