linux-kernel - Re: [PATCH 6/6] i3c: master: svc: fix random hot join failure since timeout error

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Message-ID: <ZS6d+mANtuhoAcuX@lizhi-Precision-Tower-5810>
Date:   Tue, 17 Oct 2023 10:45:14 -0400
From:   Frank Li <Frank.li@....com>
To:     Miquel Raynal <miquel.raynal@...tlin.com>
Cc:     conor.culhane@...vaco.com, alexandre.belloni@...tlin.com,
        joe@...ches.com, linux-i3c@...ts.infradead.org,
        linux-kernel@...r.kernel.org, imx@...ts.linux.dev
Subject: Re: [PATCH 6/6] i3c: master: svc: fix random hot join failure since
 timeout error

On Tue, Oct 17, 2023 at 04:33:35PM +0200, Miquel Raynal wrote:
> Hi Frank,
> 
> Frank.Li@....com wrote on Mon, 16 Oct 2023 11:32:32 -0400:
> 
> > master side report:
> >   silvaco-i3c-master 44330000.i3c-master: Error condition: MSTATUS 0x020090c7, MERRWARN 0x00100000
> > 
> > BIT 20: TIMEOUT error
> >   The module has stalled too long in a frame. This happens when:
> >   - The TX FIFO or RX FIFO is not handled and the bus is stuck in the
> > middle of a message,
> >   - No STOP was issued and between messages,
> >   - IBI manual is used and no decision was made.
> >   The maximum stall period is 10 KHz or 100 μs.
> > 
> > This is a just warning. System irq thread schedule latency is possible
> 
> 							can be bigger
> > bigger than 100us. Just omit this waring.
> 
> I'm not sure this is the correct approach. It's a real issue but there
> is not much we can do about it. Perhaps dev_err is too high, but I
> would not entirely drop this message. Maybe a comment and turning the
> message into a dbg printk would be more appropriate?

The key is not message. It return true, means IBI/HJ thread will not run.

Frank

> 
> > Fixes: dd3c52846d59 ("i3c: master: svc: Add Silvaco I3C master driver")
> > Cc: stable@...r.kernel.org
> > Signed-off-by: Frank Li <Frank.Li@....com>
> > ---
> >  drivers/i3c/master/svc-i3c-master.c | 6 ++++++
> >  1 file changed, 6 insertions(+)
> > 
> > diff --git a/drivers/i3c/master/svc-i3c-master.c b/drivers/i3c/master/svc-i3c-master.c
> > index 5bca369d6912..18bc277edc8a 100644
> > --- a/drivers/i3c/master/svc-i3c-master.c
> > +++ b/drivers/i3c/master/svc-i3c-master.c
> > @@ -93,6 +93,7 @@
> >  #define SVC_I3C_MINTMASKED   0x098
> >  #define SVC_I3C_MERRWARN     0x09C
> >  #define   SVC_I3C_MERRWARN_NACK BIT(2)
> > +#define   SVC_I3C_MERRWARN_TIMEOUT BIT(20)
> >  #define SVC_I3C_MDMACTRL     0x0A0
> >  #define SVC_I3C_MDATACTRL    0x0AC
> >  #define   SVC_I3C_MDATACTRL_FLUSHTB BIT(0)
> > @@ -225,6 +226,11 @@ static bool svc_i3c_master_error(struct svc_i3c_master *master)
> >  	if (SVC_I3C_MSTATUS_ERRWARN(mstatus)) {
> >  		merrwarn = readl(master->regs + SVC_I3C_MERRWARN);
> >  		writel(merrwarn, master->regs + SVC_I3C_MERRWARN);
> > +
> > +		/* ignore timeout error */
> > +		if (merrwarn & SVC_I3C_MERRWARN_TIMEOUT)
> > +			return false;
> > +
> >  		dev_err(master->dev,
> >  			"Error condition: MSTATUS 0x%08x, MERRWARN 0x%08x\n",
> >  			mstatus, merrwarn);
> 
> 
> Thanks,
> Miquèl