PCMCIA GPRS cards not works,help...

Russell King - ARM Linux linux at arm.linux.org.uk
Thu Feb 19 09:58:01 GMT 2004

On Thu, Feb 19, 2004 at 05:29:39PM +0800, Magikor wrote:
> Does anyone know the reason?
> Please help me,thanks a lot!

You're being rather impatient.  I haven't had a chance to look into this
at all yet.  Not everyone lives in your time zone.

It is known that the Linux PCMCIA subsystem does not support changing the
Vcc supplied to the card after the card has been initially powered up.  To
do so requires the card to first be powered down and then re-powered with
the new Vcc.

It would also appear that some PCMCIA cards report (via the hardware) that
they're 3.3V cards, but then in the CIS indicate they're 5V cards - in
other words, the usual good old quality you come to expect.

That said, commenting out that check is almost certainly wrong.  You need
to forcing req->Vcc to be the same as s->socket to ensure that we don't do
something Bad(tm).

> >----s->socket.Vcc=33,	req->Vcc=50------
> >------<6>ttyS03 at port 0xf60003f8 (irq = 46) is a 16C950/954
> >ttyS04 at port 0xf6000400 (irq = 46) is a 16C950/954
> >Division by zero in kernel.
> >.................................................
> >---Send msg CFChanged()---
> >Division by zero in kernel.

I'd suggest finding this message (its in arch/arm/kernel/*.c somewhere) and
adding a __backtrace() immediately after its printk.

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