Subject: Re: [PATCH v5 02/12] coresight: etm4x: fix underflow for nrseqstate

From: Yeoreum Yun <[email-masked]>
Date: Thu, 16 Apr 2026 18:07:38 +0100

Hi Leo,

> On Wed, Apr 15, 2026 at 05:55:18PM +0100, Yeoreum Yun wrote:
> > TCRSEQEVR<n> is implemented only when TCRIDR5.NUMSEQSTATE is 0b100,
> > in which case n ranges from 0 to 2; otherwise, TCRIDR5.NUMSEQSTATE is 0b000.
>
> My suggestion in previous version is not quite right, thanks for
> making this correct.
>
> [...]
>
> > @@ -1395,6 +1395,8 @@ static ssize_t seq_idx_store(struct device *dev,
> >  	struct etmv4_drvdata *drvdata = dev_get_drvdata(dev->parent);
> >  	struct etmv4_config *config = &drvdata->config;
> >
> > +	if (!drvdata->nrseqstate)
> > +		return -EINVAL;
>
> For "nrseqstate = 0" case, would it return -EOPNOTSUPP instead?
>
> Otherwise, LGTM:
>
> Reviewed-by: Leo Yan <[email-masked]>

Yeap. It's much better to return -ENOTSUPP in here.
I'll change it.

--
Sincerely,
Yeoreum Yun