RE: [RFC/PATCH] mwifiex: Driver - Firmware Glitches

Avinash Patil
2015-04-23T09:48:34Z

Hi Florian,

> -----Original Message-----
> From: quozl@laptop.org [mailto:quozl@laptop.org]
> Sent: Thursday, April 23, 2015 2:13 PM
> To: Florian Achleitner
> Cc: Amitkumar Karwar; Avinash Patil; linux-wireless@vger.kernel.org; Maithili
> Hinge
> Subject: Re: [RFC/PATCH] mwifiex: Driver - Firmware Glitches
>
> On Thu, Apr 23, 2015 at 10:33:02AM +0200, Florian Achleitner wrote:
> > On Friday 17 April 2015 02:45:02 Amitkumar Karwar wrote:
> > > Known firmware issues are command timeout and wakeup failure. They
> > > are not specific to SDIO. As Avinash mentioned earlier, we need to
> > > check CONFIG_MMC_DEBUG enbled dmesg logs for "write iomem (1)
> > > failed: -110" issue.
> >
> > Thx.
> > A kernel with CONFIG_MMC_DEBUG is running since 6 days on 4 devices,
> > but nothing valuable captured yet. Unfortunately, it looks like the
> > debugging code modifies the timing, such that the failure doesn't
> > occur..
>
> Yes, I've seen something similar last year, when I began to add
> instrumentation code the problems became less reproducible.
>
> So in my situation either there was a race condition with the firmware, or a
> signal integrity problem on the SDIO.
>
> I wasn't able to go into full signal integrity work at the time.
>
> I also have rather hazy memory of which particular problem I was working on.
> ;-)
>
> Perhaps you might review the effects of CONFIG_MMC_DEBUG and remove some of
> it?

As James suggested could you please check if reducing MMC_DEBUG frequency and printks only at error conditions helps?

> --
> James Cameron
> http://quozl.linux.org.au/