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From: Kyle Evans <kevans@freebsd.org>
Date: Wed, 19 May 2021 08:20:16 -0500
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Subject: Re: bcm2835
To: kamalpr@gmail.com
Cc: freebsd-arm <freebsd-arm@freebsd.org>
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On Wed, May 19, 2021 at 8:12 AM Kamal R. Prasad <kamalpr@gmail.com> wrote:
> On Wed, May 19, 2021 at 6:08 PM Kyle Evans <kevans@freebsd.org> wrote:
> >
> > On Wed, May 19, 2021 at 12:27 AM Kamal R. Prasad <kamalpr@gmail.com> wrote:
> > >
> > > hello,
> > >
> > > in file
> > > sys/arm/broadcom/bcm2835/bcm2835_sdhci.c
> > >
> > > there is a constant
> > > SDHCI_QUIRK_BROKEN_TIMEOUT_VAL
> > > can someone tell me why this was introduced and does it correspond to
> > > anything in the datasheet?
> > >
> >
> > Hi,
> >
> > This was added by gonzo@ back in r242321. It doesn't really correspond
> > to anything in the datasheet, but before I committed r354560 that
> > moved it around I did try to remove it and observed that it was still
> > a problem with either the RPi3 or RPi4.
> >
> > Thanks,
> >
> > Kyle Evans
>
> Hi!
>
> can you tell me more on why removing it was a problem for rpi3 or
> rpi4? i am trying to understand the significance of this #define.
>
> thanks
> -kamal
>

You'll find better insight from the comment at its definition and
implementation:
http://bxr.su/FreeBSD/sys/dev/sdhci/sdhci.h#60
http://bxr.su/FreeBSD/sys/dev/sdhci/sdhci.c#1814

My very vague recollection is that the advertised timeout is too low,
but it's probably an implementation issue.

Thanks,

Kyle Evans